--- old/usr/src/lib/libparted/common/lib/regexec.c	2014-07-17 16:13:46.524714479 +0200
+++ /dev/null	2014-07-17 16:13:46.000000000 +0200
@@ -1,4399 +0,0 @@
-/* Extended regular expression matching and search library.
-   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation,
-   Inc.
-   This file is part of the GNU C Library.
-   Contributed by Isamu Hasegawa <isamu@yamato.ibm.com>.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License along
-   with this program; if not, write to the Free Software Foundation,
-   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
-
-static reg_errcode_t match_ctx_init (re_match_context_t *cache, int eflags,
-				     Idx n) internal_function;
-static void match_ctx_clean (re_match_context_t *mctx) internal_function;
-static void match_ctx_free (re_match_context_t *cache) internal_function;
-static reg_errcode_t match_ctx_add_entry (re_match_context_t *cache, Idx node,
-					  Idx str_idx, Idx from, Idx to)
-     internal_function;
-static Idx search_cur_bkref_entry (const re_match_context_t *mctx, Idx str_idx)
-     internal_function;
-static reg_errcode_t match_ctx_add_subtop (re_match_context_t *mctx, Idx node,
-					   Idx str_idx) internal_function;
-static re_sub_match_last_t * match_ctx_add_sublast (re_sub_match_top_t *subtop,
-						    Idx node, Idx str_idx)
-     internal_function;
-static void sift_ctx_init (re_sift_context_t *sctx, re_dfastate_t **sifted_sts,
-			   re_dfastate_t **limited_sts, Idx last_node,
-			   Idx last_str_idx)
-     internal_function;
-static reg_errcode_t re_search_internal (const regex_t *preg,
-					 const char *string, Idx length,
-					 Idx start, Idx last_start, Idx stop,
-					 size_t nmatch, regmatch_t pmatch[],
-					 int eflags) internal_function;
-static regoff_t re_search_2_stub (struct re_pattern_buffer *bufp,
-				  const char *string1, Idx length1,
-				  const char *string2, Idx length2,
-				  Idx start, regoff_t range,
-				  struct re_registers *regs,
-				  Idx stop, bool ret_len) internal_function;
-static regoff_t re_search_stub (struct re_pattern_buffer *bufp,
-				const char *string, Idx length, Idx start,
-				regoff_t range, Idx stop,
-				struct re_registers *regs,
-				bool ret_len) internal_function;
-static unsigned int re_copy_regs (struct re_registers *regs, regmatch_t *pmatch,
-				  Idx nregs, int regs_allocated)
-     internal_function;
-static reg_errcode_t prune_impossible_nodes (re_match_context_t *mctx)
-     internal_function;
-static Idx check_matching (re_match_context_t *mctx, bool fl_longest_match,
-			   Idx *p_match_first) internal_function;
-static Idx check_halt_state_context (const re_match_context_t *mctx,
-				     const re_dfastate_t *state, Idx idx)
-     internal_function;
-static void update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
-			 regmatch_t *prev_idx_match, Idx cur_node,
-			 Idx cur_idx, Idx nmatch) internal_function;
-static reg_errcode_t push_fail_stack (struct re_fail_stack_t *fs,
-				      Idx str_idx, Idx dest_node, Idx nregs,
-				      regmatch_t *regs,
-				      re_node_set *eps_via_nodes)
-     internal_function;
-static reg_errcode_t set_regs (const regex_t *preg,
-			       const re_match_context_t *mctx,
-			       size_t nmatch, regmatch_t *pmatch,
-			       bool fl_backtrack) internal_function;
-static reg_errcode_t free_fail_stack_return (struct re_fail_stack_t *fs)
-     internal_function;
-
-#ifdef RE_ENABLE_I18N
-static int sift_states_iter_mb (const re_match_context_t *mctx,
-				re_sift_context_t *sctx,
-				Idx node_idx, Idx str_idx, Idx max_str_idx)
-     internal_function;
-#endif /* RE_ENABLE_I18N */
-static reg_errcode_t sift_states_backward (const re_match_context_t *mctx,
-					   re_sift_context_t *sctx)
-     internal_function;
-static reg_errcode_t build_sifted_states (const re_match_context_t *mctx,
-					  re_sift_context_t *sctx, Idx str_idx,
-					  re_node_set *cur_dest)
-     internal_function;
-static reg_errcode_t update_cur_sifted_state (const re_match_context_t *mctx,
-					      re_sift_context_t *sctx,
-					      Idx str_idx,
-					      re_node_set *dest_nodes)
-     internal_function;
-static reg_errcode_t add_epsilon_src_nodes (const re_dfa_t *dfa,
-					    re_node_set *dest_nodes,
-					    const re_node_set *candidates)
-     internal_function;
-static bool check_dst_limits (const re_match_context_t *mctx,
-			      const re_node_set *limits,
-			      Idx dst_node, Idx dst_idx, Idx src_node,
-			      Idx src_idx) internal_function;
-static int check_dst_limits_calc_pos_1 (const re_match_context_t *mctx,
-					int boundaries, Idx subexp_idx,
-					Idx from_node, Idx bkref_idx)
-     internal_function;
-static int check_dst_limits_calc_pos (const re_match_context_t *mctx,
-				      Idx limit, Idx subexp_idx,
-				      Idx node, Idx str_idx,
-				      Idx bkref_idx) internal_function;
-static reg_errcode_t check_subexp_limits (const re_dfa_t *dfa,
-					  re_node_set *dest_nodes,
-					  const re_node_set *candidates,
-					  re_node_set *limits,
-					  struct re_backref_cache_entry *bkref_ents,
-					  Idx str_idx) internal_function;
-static reg_errcode_t sift_states_bkref (const re_match_context_t *mctx,
-					re_sift_context_t *sctx,
-					Idx str_idx, const re_node_set *candidates)
-     internal_function;
-static reg_errcode_t merge_state_array (const re_dfa_t *dfa,
-					re_dfastate_t **dst,
-					re_dfastate_t **src, Idx num)
-     internal_function;
-static re_dfastate_t *find_recover_state (reg_errcode_t *err,
-					 re_match_context_t *mctx) internal_function;
-static re_dfastate_t *transit_state (reg_errcode_t *err,
-				     re_match_context_t *mctx,
-				     re_dfastate_t *state) internal_function;
-static re_dfastate_t *merge_state_with_log (reg_errcode_t *err,
-					    re_match_context_t *mctx,
-					    re_dfastate_t *next_state)
-     internal_function;
-static reg_errcode_t check_subexp_matching_top (re_match_context_t *mctx,
-						re_node_set *cur_nodes,
-						Idx str_idx) internal_function;
-#if 0
-static re_dfastate_t *transit_state_sb (reg_errcode_t *err,
-					re_match_context_t *mctx,
-					re_dfastate_t *pstate)
-     internal_function;
-#endif
-#ifdef RE_ENABLE_I18N
-static reg_errcode_t transit_state_mb (re_match_context_t *mctx,
-				       re_dfastate_t *pstate)
-     internal_function;
-#endif /* RE_ENABLE_I18N */
-static reg_errcode_t transit_state_bkref (re_match_context_t *mctx,
-					  const re_node_set *nodes)
-     internal_function;
-static reg_errcode_t get_subexp (re_match_context_t *mctx,
-				 Idx bkref_node, Idx bkref_str_idx)
-     internal_function;
-static reg_errcode_t get_subexp_sub (re_match_context_t *mctx,
-				     const re_sub_match_top_t *sub_top,
-				     re_sub_match_last_t *sub_last,
-				     Idx bkref_node, Idx bkref_str)
-     internal_function;
-static Idx find_subexp_node (const re_dfa_t *dfa, const re_node_set *nodes,
-			     Idx subexp_idx, int type) internal_function;
-static reg_errcode_t check_arrival (re_match_context_t *mctx,
-				    state_array_t *path, Idx top_node,
-				    Idx top_str, Idx last_node, Idx last_str,
-				    int type) internal_function;
-static reg_errcode_t check_arrival_add_next_nodes (re_match_context_t *mctx,
-						   Idx str_idx,
-						   re_node_set *cur_nodes,
-						   re_node_set *next_nodes)
-     internal_function;
-static reg_errcode_t check_arrival_expand_ecl (const re_dfa_t *dfa,
-					       re_node_set *cur_nodes,
-					       Idx ex_subexp, int type)
-     internal_function;
-static reg_errcode_t check_arrival_expand_ecl_sub (const re_dfa_t *dfa,
-						   re_node_set *dst_nodes,
-						   Idx target, Idx ex_subexp,
-						   int type) internal_function;
-static reg_errcode_t expand_bkref_cache (re_match_context_t *mctx,
-					 re_node_set *cur_nodes, Idx cur_str,
-					 Idx subexp_num, int type)
-     internal_function;
-static bool build_trtable (const re_dfa_t *dfa,
-			   re_dfastate_t *state) internal_function;
-#ifdef RE_ENABLE_I18N
-static int check_node_accept_bytes (const re_dfa_t *dfa, Idx node_idx,
-				    const re_string_t *input, Idx idx)
-     internal_function;
-# ifdef _LIBC
-static unsigned int find_collation_sequence_value (const unsigned char *mbs,
-						   size_t name_len)
-     internal_function;
-# endif /* _LIBC */
-#endif /* RE_ENABLE_I18N */
-static Idx group_nodes_into_DFAstates (const re_dfa_t *dfa,
-				       const re_dfastate_t *state,
-				       re_node_set *states_node,
-				       bitset_t *states_ch) internal_function;
-static bool check_node_accept (const re_match_context_t *mctx,
-			       const re_token_t *node, Idx idx)
-     internal_function;
-static reg_errcode_t extend_buffers (re_match_context_t *mctx)
-     internal_function;
-
-/* Entry point for POSIX code.  */
-
-/* regexec searches for a given pattern, specified by PREG, in the
-   string STRING.
-
-   If NMATCH is zero or REG_NOSUB was set in the cflags argument to
-   `regcomp', we ignore PMATCH.  Otherwise, we assume PMATCH has at
-   least NMATCH elements, and we set them to the offsets of the
-   corresponding matched substrings.
-
-   EFLAGS specifies `execution flags' which affect matching: if
-   REG_NOTBOL is set, then ^ does not match at the beginning of the
-   string; if REG_NOTEOL is set, then $ does not match at the end.
-
-   We return 0 if we find a match and REG_NOMATCH if not.  */
-
-int
-regexec (preg, string, nmatch, pmatch, eflags)
-    const regex_t *_Restrict_ preg;
-    const char *_Restrict_ string;
-    size_t nmatch;
-    regmatch_t pmatch[_Restrict_arr_];
-    int eflags;
-{
-  reg_errcode_t err;
-  Idx start, length;
-#ifdef _LIBC
-  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
-#endif
-
-  if (eflags & ~(REG_NOTBOL | REG_NOTEOL | REG_STARTEND))
-    return REG_BADPAT;
-
-  if (eflags & REG_STARTEND)
-    {
-      start = pmatch[0].rm_so;
-      length = pmatch[0].rm_eo;
-    }
-  else
-    {
-      start = 0;
-      length = strlen (string);
-    }
-
-  __libc_lock_lock (dfa->lock);
-  if (preg->no_sub)
-    err = re_search_internal (preg, string, length, start, length,
-			      length, 0, NULL, eflags);
-  else
-    err = re_search_internal (preg, string, length, start, length,
-			      length, nmatch, pmatch, eflags);
-  __libc_lock_unlock (dfa->lock);
-  return err != REG_NOERROR;
-}
-
-#ifdef _LIBC
-# include <shlib-compat.h>
-versioned_symbol (libc, __regexec, regexec, GLIBC_2_3_4);
-
-# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3_4)
-__typeof__ (__regexec) __compat_regexec;
-
-int
-attribute_compat_text_section
-__compat_regexec (const regex_t *_Restrict_ preg,
-		  const char *_Restrict_ string, size_t nmatch,
-		  regmatch_t pmatch[], int eflags)
-{
-  return regexec (preg, string, nmatch, pmatch,
-		  eflags & (REG_NOTBOL | REG_NOTEOL));
-}
-compat_symbol (libc, __compat_regexec, regexec, GLIBC_2_0);
-# endif
-#endif
-
-/* Entry points for GNU code.  */
-
-/* re_match, re_search, re_match_2, re_search_2
-
-   The former two functions operate on STRING with length LENGTH,
-   while the later two operate on concatenation of STRING1 and STRING2
-   with lengths LENGTH1 and LENGTH2, respectively.
-
-   re_match() matches the compiled pattern in BUFP against the string,
-   starting at index START.
-
-   re_search() first tries matching at index START, then it tries to match
-   starting from index START + 1, and so on.  The last start position tried
-   is START + RANGE.  (Thus RANGE = 0 forces re_search to operate the same
-   way as re_match().)
-
-   The parameter STOP of re_{match,search}_2 specifies that no match exceeding
-   the first STOP characters of the concatenation of the strings should be
-   concerned.
-
-   If REGS is not NULL, and BUFP->no_sub is not set, the offsets of the match
-   and all groups is stored in REGS.  (For the "_2" variants, the offsets are
-   computed relative to the concatenation, not relative to the individual
-   strings.)
-
-   On success, re_match* functions return the length of the match, re_search*
-   return the position of the start of the match.  Return value -1 means no
-   match was found and -2 indicates an internal error.  */
-
-regoff_t
-re_match (bufp, string, length, start, regs)
-    struct re_pattern_buffer *bufp;
-    const char *string;
-    Idx length, start;
-    struct re_registers *regs;
-{
-  return re_search_stub (bufp, string, length, start, 0, length, regs, true);
-}
-#ifdef _LIBC
-weak_alias (__re_match, re_match)
-#endif
-
-regoff_t
-re_search (bufp, string, length, start, range, regs)
-    struct re_pattern_buffer *bufp;
-    const char *string;
-    Idx length, start;
-    regoff_t range;
-    struct re_registers *regs;
-{
-  return re_search_stub (bufp, string, length, start, range, length, regs,
-			 false);
-}
-#ifdef _LIBC
-weak_alias (__re_search, re_search)
-#endif
-
-regoff_t
-re_match_2 (bufp, string1, length1, string2, length2, start, regs, stop)
-    struct re_pattern_buffer *bufp;
-    const char *string1, *string2;
-    Idx length1, length2, start, stop;
-    struct re_registers *regs;
-{
-  return re_search_2_stub (bufp, string1, length1, string2, length2,
-			   start, 0, regs, stop, true);
-}
-#ifdef _LIBC
-weak_alias (__re_match_2, re_match_2)
-#endif
-
-regoff_t
-re_search_2 (bufp, string1, length1, string2, length2, start, range, regs, stop)
-    struct re_pattern_buffer *bufp;
-    const char *string1, *string2;
-    Idx length1, length2, start, stop;
-    regoff_t range;
-    struct re_registers *regs;
-{
-  return re_search_2_stub (bufp, string1, length1, string2, length2,
-			   start, range, regs, stop, false);
-}
-#ifdef _LIBC
-weak_alias (__re_search_2, re_search_2)
-#endif
-
-static regoff_t
-internal_function
-re_search_2_stub (struct re_pattern_buffer *bufp,
-		  const char *string1, Idx length1,
-		  const char *string2, Idx length2,
-		  Idx start, regoff_t range, struct re_registers *regs,
-		  Idx stop, bool ret_len)
-{
-  const char *str;
-  regoff_t rval;
-  Idx len = length1 + length2;
-  char *s = NULL;
-
-  if (BE (length1 < 0 || length2 < 0 || stop < 0 || len < length1, 0))
-    return -2;
-
-  /* Concatenate the strings.  */
-  if (length2 > 0)
-    if (length1 > 0)
-      {
-	s = re_malloc (char, len);
-
-	if (BE (s == NULL, 0))
-	  return -2;
-#ifdef _LIBC
-	memcpy (__mempcpy (s, string1, length1), string2, length2);
-#else
-	memcpy (s, string1, length1);
-	memcpy (s + length1, string2, length2);
-#endif
-	str = s;
-      }
-    else
-      str = string2;
-  else
-    str = string1;
-
-  rval = re_search_stub (bufp, str, len, start, range, stop, regs,
-			 ret_len);
-  re_free (s);
-  return rval;
-}
-
-/* The parameters have the same meaning as those of re_search.
-   Additional parameters:
-   If RET_LEN is true the length of the match is returned (re_match style);
-   otherwise the position of the match is returned.  */
-
-static regoff_t
-internal_function
-re_search_stub (struct re_pattern_buffer *bufp,
-		const char *string, Idx length,
-		Idx start, regoff_t range, Idx stop, struct re_registers *regs,
-		bool ret_len)
-{
-  reg_errcode_t result;
-  regmatch_t *pmatch;
-  Idx nregs;
-  regoff_t rval;
-  int eflags = 0;
-#ifdef _LIBC
-  re_dfa_t *dfa = (re_dfa_t *) bufp->buffer;
-#endif
-  Idx last_start = start + range;
-
-  /* Check for out-of-range.  */
-  if (BE (start < 0 || start > length, 0))
-    return -1;
-  if (BE (length < last_start || (0 <= range && last_start < start), 0))
-    last_start = length;
-  else if (BE (last_start < 0 || (range < 0 && start <= last_start), 0))
-    last_start = 0;
-
-  __libc_lock_lock (dfa->lock);
-
-  eflags |= (bufp->not_bol) ? REG_NOTBOL : 0;
-  eflags |= (bufp->not_eol) ? REG_NOTEOL : 0;
-
-  /* Compile fastmap if we haven't yet.  */
-  if (start < last_start && bufp->fastmap != NULL && !bufp->fastmap_accurate)
-    re_compile_fastmap (bufp);
-
-  if (BE (bufp->no_sub, 0))
-    regs = NULL;
-
-  /* We need at least 1 register.  */
-  if (regs == NULL)
-    nregs = 1;
-  else if (BE (bufp->regs_allocated == REGS_FIXED
-	       && regs->num_regs <= bufp->re_nsub, 0))
-    {
-      nregs = regs->num_regs;
-      if (BE (nregs < 1, 0))
-	{
-	  /* Nothing can be copied to regs.  */
-	  regs = NULL;
-	  nregs = 1;
-	}
-    }
-  else
-    nregs = bufp->re_nsub + 1;
-  pmatch = re_malloc (regmatch_t, nregs);
-  if (BE (pmatch == NULL, 0))
-    {
-      rval = -2;
-      goto out;
-    }
-
-  result = re_search_internal (bufp, string, length, start, last_start, stop,
-			       nregs, pmatch, eflags);
-
-  rval = 0;
-
-  /* I hope we needn't fill ther regs with -1's when no match was found.  */
-  if (result != REG_NOERROR)
-    rval = -1;
-  else if (regs != NULL)
-    {
-      /* If caller wants register contents data back, copy them.  */
-      bufp->regs_allocated = re_copy_regs (regs, pmatch, nregs,
-					   bufp->regs_allocated);
-      if (BE (bufp->regs_allocated == REGS_UNALLOCATED, 0))
-	rval = -2;
-    }
-
-  if (BE (rval == 0, 1))
-    {
-      if (ret_len)
-	{
-	  assert (pmatch[0].rm_so == start);
-	  rval = pmatch[0].rm_eo - start;
-	}
-      else
-	rval = pmatch[0].rm_so;
-    }
-  re_free (pmatch);
- out:
-  __libc_lock_unlock (dfa->lock);
-  return rval;
-}
-
-static unsigned int
-internal_function
-re_copy_regs (struct re_registers *regs, regmatch_t *pmatch, Idx nregs,
-	      int regs_allocated)
-{
-  int rval = REGS_REALLOCATE;
-  Idx i;
-  Idx need_regs = nregs + 1;
-  /* We need one extra element beyond `num_regs' for the `-1' marker GNU code
-     uses.  */
-
-  /* Have the register data arrays been allocated?  */
-  if (regs_allocated == REGS_UNALLOCATED)
-    { /* No.  So allocate them with malloc.  */
-      regs->start = re_malloc (regoff_t, need_regs);
-      if (BE (regs->start == NULL, 0))
-	return REGS_UNALLOCATED;
-      regs->end = re_malloc (regoff_t, need_regs);
-      if (BE (regs->end == NULL, 0))
-	{
-	  re_free (regs->start);
-	  return REGS_UNALLOCATED;
-	}
-      regs->num_regs = need_regs;
-    }
-  else if (regs_allocated == REGS_REALLOCATE)
-    { /* Yes.  If we need more elements than were already
-	 allocated, reallocate them.  If we need fewer, just
-	 leave it alone.  */
-      if (BE (need_regs > regs->num_regs, 0))
-	{
-	  regoff_t *new_start = re_realloc (regs->start, regoff_t, need_regs);
-	  regoff_t *new_end;
-	  if (BE (new_start == NULL, 0))
-	    return REGS_UNALLOCATED;
-	  new_end = re_realloc (regs->end, regoff_t, need_regs);
-	  if (BE (new_end == NULL, 0))
-	    {
-	      re_free (new_start);
-	      return REGS_UNALLOCATED;
-	    }
-	  regs->start = new_start;
-	  regs->end = new_end;
-	  regs->num_regs = need_regs;
-	}
-    }
-  else
-    {
-      assert (regs_allocated == REGS_FIXED);
-      /* This function may not be called with REGS_FIXED and nregs too big.  */
-      assert (regs->num_regs >= nregs);
-      rval = REGS_FIXED;
-    }
-
-  /* Copy the regs.  */
-  for (i = 0; i < nregs; ++i)
-    {
-      regs->start[i] = pmatch[i].rm_so;
-      regs->end[i] = pmatch[i].rm_eo;
-    }
-  for ( ; i < regs->num_regs; ++i)
-    regs->start[i] = regs->end[i] = -1;
-
-  return rval;
-}
-
-/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
-   ENDS.  Subsequent matches using PATTERN_BUFFER and REGS will use
-   this memory for recording register information.  STARTS and ENDS
-   must be allocated using the malloc library routine, and must each
-   be at least NUM_REGS * sizeof (regoff_t) bytes long.
-
-   If NUM_REGS == 0, then subsequent matches should allocate their own
-   register data.
-
-   Unless this function is called, the first search or match using
-   PATTERN_BUFFER will allocate its own register data, without
-   freeing the old data.  */
-
-void
-re_set_registers (bufp, regs, num_regs, starts, ends)
-    struct re_pattern_buffer *bufp;
-    struct re_registers *regs;
-    __re_size_t num_regs;
-    regoff_t *starts, *ends;
-{
-  if (num_regs)
-    {
-      bufp->regs_allocated = REGS_REALLOCATE;
-      regs->num_regs = num_regs;
-      regs->start = starts;
-      regs->end = ends;
-    }
-  else
-    {
-      bufp->regs_allocated = REGS_UNALLOCATED;
-      regs->num_regs = 0;
-      regs->start = regs->end = NULL;
-    }
-}
-#ifdef _LIBC
-weak_alias (__re_set_registers, re_set_registers)
-#endif
-
-/* Entry points compatible with 4.2 BSD regex library.  We don't define
-   them unless specifically requested.  */
-
-#if defined _REGEX_RE_COMP || defined _LIBC
-int
-# ifdef _LIBC
-weak_function
-# endif
-re_exec (s)
-     const char *s;
-{
-  return 0 == regexec (&re_comp_buf, s, 0, NULL, 0);
-}
-#endif /* _REGEX_RE_COMP */
-
-/* Internal entry point.  */
-
-/* Searches for a compiled pattern PREG in the string STRING, whose
-   length is LENGTH.  NMATCH, PMATCH, and EFLAGS have the same
-   meaning as with regexec.  LAST_START is START + RANGE, where
-   START and RANGE have the same meaning as with re_search.
-   Return REG_NOERROR if we find a match, and REG_NOMATCH if not,
-   otherwise return the error code.
-   Note: We assume front end functions already check ranges.
-   (0 <= LAST_START && LAST_START <= LENGTH)  */
-
-static reg_errcode_t
-internal_function
-re_search_internal (const regex_t *preg,
-		    const char *string, Idx length,
-		    Idx start, Idx last_start, Idx stop,
-		    size_t nmatch, regmatch_t pmatch[],
-		    int eflags)
-{
-  reg_errcode_t err;
-  const re_dfa_t *dfa = (const re_dfa_t *) preg->buffer;
-  Idx left_lim, right_lim;
-  int incr;
-  bool fl_longest_match;
-  int match_kind;
-  Idx match_first;
-  Idx match_last = REG_MISSING;
-  Idx extra_nmatch;
-  bool sb;
-  int ch;
-#if defined _LIBC || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)
-  re_match_context_t mctx = { .dfa = dfa };
-#else
-  re_match_context_t mctx;
-#endif
-  char *fastmap = ((preg->fastmap != NULL && preg->fastmap_accurate
-		    && start != last_start && !preg->can_be_null)
-		   ? preg->fastmap : NULL);
-  RE_TRANSLATE_TYPE t = preg->translate;
-
-#if !(defined _LIBC || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
-  memset (&mctx, '\0', sizeof (re_match_context_t));
-  mctx.dfa = dfa;
-#endif
-
-  extra_nmatch = (nmatch > preg->re_nsub) ? nmatch - (preg->re_nsub + 1) : 0;
-  nmatch -= extra_nmatch;
-
-  /* Check if the DFA haven't been compiled.  */
-  if (BE (preg->used == 0 || dfa->init_state == NULL
-	  || dfa->init_state_word == NULL || dfa->init_state_nl == NULL
-	  || dfa->init_state_begbuf == NULL, 0))
-    return REG_NOMATCH;
-
-#ifdef DEBUG
-  /* We assume front-end functions already check them.  */
-  assert (0 <= last_start && last_start <= length);
-#endif
-
-  /* If initial states with non-begbuf contexts have no elements,
-     the regex must be anchored.  If preg->newline_anchor is set,
-     we'll never use init_state_nl, so do not check it.  */
-  if (dfa->init_state->nodes.nelem == 0
-      && dfa->init_state_word->nodes.nelem == 0
-      && (dfa->init_state_nl->nodes.nelem == 0
-	  || !preg->newline_anchor))
-    {
-      if (start != 0 && last_start != 0)
-        return REG_NOMATCH;
-      start = last_start = 0;
-    }
-
-  /* We must check the longest matching, if nmatch > 0.  */
-  fl_longest_match = (nmatch != 0 || dfa->nbackref);
-
-  err = re_string_allocate (&mctx.input, string, length, dfa->nodes_len + 1,
-			    preg->translate, preg->syntax & RE_ICASE, dfa);
-  if (BE (err != REG_NOERROR, 0))
-    goto free_return;
-  mctx.input.stop = stop;
-  mctx.input.raw_stop = stop;
-  mctx.input.newline_anchor = preg->newline_anchor;
-
-  err = match_ctx_init (&mctx, eflags, dfa->nbackref * 2);
-  if (BE (err != REG_NOERROR, 0))
-    goto free_return;
-
-  /* We will log all the DFA states through which the dfa pass,
-     if nmatch > 1, or this dfa has "multibyte node", which is a
-     back-reference or a node which can accept multibyte character or
-     multi character collating element.  */
-  if (nmatch > 1 || dfa->has_mb_node)
-    {
-      /* Avoid overflow.  */
-      if (BE (SIZE_MAX / sizeof (re_dfastate_t *) <= mctx.input.bufs_len, 0))
-	{
-	  err = REG_ESPACE;
-	  goto free_return;
-	}
-
-      mctx.state_log = re_malloc (re_dfastate_t *, mctx.input.bufs_len + 1);
-      if (BE (mctx.state_log == NULL, 0))
-	{
-	  err = REG_ESPACE;
-	  goto free_return;
-	}
-    }
-  else
-    mctx.state_log = NULL;
-
-  match_first = start;
-  mctx.input.tip_context = (eflags & REG_NOTBOL) ? CONTEXT_BEGBUF
-			   : CONTEXT_NEWLINE | CONTEXT_BEGBUF;
-
-  /* Check incrementally whether of not the input string match.  */
-  incr = (last_start < start) ? -1 : 1;
-  left_lim = (last_start < start) ? last_start : start;
-  right_lim = (last_start < start) ? start : last_start;
-  sb = dfa->mb_cur_max == 1;
-  match_kind =
-    (fastmap
-     ? ((sb || !(preg->syntax & RE_ICASE || t) ? 4 : 0)
-	| (start <= last_start ? 2 : 0)
-	| (t != NULL ? 1 : 0))
-     : 8);
-
-  for (;; match_first += incr)
-    {
-      err = REG_NOMATCH;
-      if (match_first < left_lim || right_lim < match_first)
-	goto free_return;
-
-      /* Advance as rapidly as possible through the string, until we
-	 find a plausible place to start matching.  This may be done
-	 with varying efficiency, so there are various possibilities:
-	 only the most common of them are specialized, in order to
-	 save on code size.  We use a switch statement for speed.  */
-      switch (match_kind)
-	{
-	case 8:
-	  /* No fastmap.  */
-	  break;
-
-	case 7:
-	  /* Fastmap with single-byte translation, match forward.  */
-	  while (BE (match_first < right_lim, 1)
-		 && !fastmap[t[(unsigned char) string[match_first]]])
-	    ++match_first;
-	  goto forward_match_found_start_or_reached_end;
-
-	case 6:
-	  /* Fastmap without translation, match forward.  */
-	  while (BE (match_first < right_lim, 1)
-		 && !fastmap[(unsigned char) string[match_first]])
-	    ++match_first;
-
-	forward_match_found_start_or_reached_end:
-	  if (BE (match_first == right_lim, 0))
-	    {
-	      ch = match_first >= length
-		       ? 0 : (unsigned char) string[match_first];
-	      if (!fastmap[t ? t[ch] : ch])
-		goto free_return;
-	    }
-	  break;
-
-	case 4:
-	case 5:
-	  /* Fastmap without multi-byte translation, match backwards.  */
-	  while (match_first >= left_lim)
-	    {
-	      ch = match_first >= length
-		       ? 0 : (unsigned char) string[match_first];
-	      if (fastmap[t ? t[ch] : ch])
-		break;
-	      --match_first;
-	    }
-	  if (match_first < left_lim)
-	    goto free_return;
-	  break;
-
-	default:
-	  /* In this case, we can't determine easily the current byte,
-	     since it might be a component byte of a multibyte
-	     character.  Then we use the constructed buffer instead.  */
-	  for (;;)
-	    {
-	      /* If MATCH_FIRST is out of the valid range, reconstruct the
-		 buffers.  */
-	      __re_size_t offset = match_first - mctx.input.raw_mbs_idx;
-	      if (BE (offset >= (__re_size_t) mctx.input.valid_raw_len, 0))
-		{
-		  err = re_string_reconstruct (&mctx.input, match_first,
-					       eflags);
-		  if (BE (err != REG_NOERROR, 0))
-		    goto free_return;
-
-		  offset = match_first - mctx.input.raw_mbs_idx;
-		}
-	      /* If MATCH_FIRST is out of the buffer, leave it as '\0'.
-		 Note that MATCH_FIRST must not be smaller than 0.  */
-	      ch = (match_first >= length
-		    ? 0 : re_string_byte_at (&mctx.input, offset));
-	      if (fastmap[ch])
-		break;
-	      match_first += incr;
-	      if (match_first < left_lim || match_first > right_lim)
-	        {
-	          err = REG_NOMATCH;
-	          goto free_return;
-	        }
-	    }
-	  break;
-	}
-
-      /* Reconstruct the buffers so that the matcher can assume that
-	 the matching starts from the beginning of the buffer.  */
-      err = re_string_reconstruct (&mctx.input, match_first, eflags);
-      if (BE (err != REG_NOERROR, 0))
-	goto free_return;
-
-#ifdef RE_ENABLE_I18N
-     /* Don't consider this char as a possible match start if it part,
-	yet isn't the head, of a multibyte character.  */
-      if (!sb && !re_string_first_byte (&mctx.input, 0))
-	continue;
-#endif
-
-      /* It seems to be appropriate one, then use the matcher.  */
-      /* We assume that the matching starts from 0.  */
-      mctx.state_log_top = mctx.nbkref_ents = mctx.max_mb_elem_len = 0;
-      match_last = check_matching (&mctx, fl_longest_match,
-				   start <= last_start ? &match_first : NULL);
-      if (match_last != REG_MISSING)
-	{
-	  if (BE (match_last == REG_ERROR, 0))
-	    {
-	      err = REG_ESPACE;
-	      goto free_return;
-	    }
-	  else
-	    {
-	      mctx.match_last = match_last;
-	      if ((!preg->no_sub && nmatch > 1) || dfa->nbackref)
-		{
-		  re_dfastate_t *pstate = mctx.state_log[match_last];
-		  mctx.last_node = check_halt_state_context (&mctx, pstate,
-							     match_last);
-		}
-	      if ((!preg->no_sub && nmatch > 1 && dfa->has_plural_match)
-		  || dfa->nbackref)
-		{
-		  err = prune_impossible_nodes (&mctx);
-		  if (err == REG_NOERROR)
-		    break;
-		  if (BE (err != REG_NOMATCH, 0))
-		    goto free_return;
-		  match_last = REG_MISSING;
-		}
-	      else
-		break; /* We found a match.  */
-	    }
-	}
-
-      match_ctx_clean (&mctx);
-    }
-
-#ifdef DEBUG
-  assert (match_last != REG_MISSING);
-  assert (err == REG_NOERROR);
-#endif
-
-  /* Set pmatch[] if we need.  */
-  if (nmatch > 0)
-    {
-      Idx reg_idx;
-
-      /* Initialize registers.  */
-      for (reg_idx = 1; reg_idx < nmatch; ++reg_idx)
-	pmatch[reg_idx].rm_so = pmatch[reg_idx].rm_eo = -1;
-
-      /* Set the points where matching start/end.  */
-      pmatch[0].rm_so = 0;
-      pmatch[0].rm_eo = mctx.match_last;
-      /* FIXME: This function should fail if mctx.match_last exceeds
-	 the maximum possible regoff_t value.  We need a new error
-	 code REG_OVERFLOW.  */
-
-      if (!preg->no_sub && nmatch > 1)
-	{
-	  err = set_regs (preg, &mctx, nmatch, pmatch,
-			  dfa->has_plural_match && dfa->nbackref > 0);
-	  if (BE (err != REG_NOERROR, 0))
-	    goto free_return;
-	}
-
-      /* At last, add the offset to the each registers, since we slided
-	 the buffers so that we could assume that the matching starts
-	 from 0.  */
-      for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
-	if (pmatch[reg_idx].rm_so != -1)
-	  {
-#ifdef RE_ENABLE_I18N
-	    if (BE (mctx.input.offsets_needed != 0, 0))
-	      {
-		pmatch[reg_idx].rm_so =
-		  (pmatch[reg_idx].rm_so == mctx.input.valid_len
-		   ? mctx.input.valid_raw_len
-		   : mctx.input.offsets[pmatch[reg_idx].rm_so]);
-		pmatch[reg_idx].rm_eo =
-		  (pmatch[reg_idx].rm_eo == mctx.input.valid_len
-		   ? mctx.input.valid_raw_len
-		   : mctx.input.offsets[pmatch[reg_idx].rm_eo]);
-	      }
-#else
-	    assert (mctx.input.offsets_needed == 0);
-#endif
-	    pmatch[reg_idx].rm_so += match_first;
-	    pmatch[reg_idx].rm_eo += match_first;
-	  }
-      for (reg_idx = 0; reg_idx < extra_nmatch; ++reg_idx)
-	{
-	  pmatch[nmatch + reg_idx].rm_so = -1;
-	  pmatch[nmatch + reg_idx].rm_eo = -1;
-	}
-
-      if (dfa->subexp_map)
-        for (reg_idx = 0; reg_idx + 1 < nmatch; reg_idx++)
-          if (dfa->subexp_map[reg_idx] != reg_idx)
-            {
-              pmatch[reg_idx + 1].rm_so
-                = pmatch[dfa->subexp_map[reg_idx] + 1].rm_so;
-              pmatch[reg_idx + 1].rm_eo
-                = pmatch[dfa->subexp_map[reg_idx] + 1].rm_eo;
-            }
-    }
-
- free_return:
-  re_free (mctx.state_log);
-  if (dfa->nbackref)
-    match_ctx_free (&mctx);
-  re_string_destruct (&mctx.input);
-  return err;
-}
-
-static reg_errcode_t
-internal_function
-prune_impossible_nodes (re_match_context_t *mctx)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  Idx halt_node, match_last;
-  reg_errcode_t ret;
-  re_dfastate_t **sifted_states;
-  re_dfastate_t **lim_states = NULL;
-  re_sift_context_t sctx;
-#ifdef DEBUG
-  assert (mctx->state_log != NULL);
-#endif
-  match_last = mctx->match_last;
-  halt_node = mctx->last_node;
-
-  /* Avoid overflow.  */
-  if (BE (SIZE_MAX / sizeof (re_dfastate_t *) <= match_last, 0))
-    return REG_ESPACE;
-
-  sifted_states = re_malloc (re_dfastate_t *, match_last + 1);
-  if (BE (sifted_states == NULL, 0))
-    {
-      ret = REG_ESPACE;
-      goto free_return;
-    }
-  if (dfa->nbackref)
-    {
-      lim_states = re_malloc (re_dfastate_t *, match_last + 1);
-      if (BE (lim_states == NULL, 0))
-	{
-	  ret = REG_ESPACE;
-	  goto free_return;
-	}
-      while (1)
-	{
-	  memset (lim_states, '\0',
-		  sizeof (re_dfastate_t *) * (match_last + 1));
-	  sift_ctx_init (&sctx, sifted_states, lim_states, halt_node,
-			 match_last);
-	  ret = sift_states_backward (mctx, &sctx);
-	  re_node_set_free (&sctx.limits);
-	  if (BE (ret != REG_NOERROR, 0))
-	      goto free_return;
-	  if (sifted_states[0] != NULL || lim_states[0] != NULL)
-	    break;
-	  do
-	    {
-	      --match_last;
-	      if (! REG_VALID_INDEX (match_last))
-		{
-		  ret = REG_NOMATCH;
-		  goto free_return;
-		}
-	    } while (mctx->state_log[match_last] == NULL
-		     || !mctx->state_log[match_last]->halt);
-	  halt_node = check_halt_state_context (mctx,
-						mctx->state_log[match_last],
-						match_last);
-	}
-      ret = merge_state_array (dfa, sifted_states, lim_states,
-			       match_last + 1);
-      re_free (lim_states);
-      lim_states = NULL;
-      if (BE (ret != REG_NOERROR, 0))
-	goto free_return;
-    }
-  else
-    {
-      sift_ctx_init (&sctx, sifted_states, lim_states, halt_node, match_last);
-      ret = sift_states_backward (mctx, &sctx);
-      re_node_set_free (&sctx.limits);
-      if (BE (ret != REG_NOERROR, 0))
-	goto free_return;
-    }
-  re_free (mctx->state_log);
-  mctx->state_log = sifted_states;
-  sifted_states = NULL;
-  mctx->last_node = halt_node;
-  mctx->match_last = match_last;
-  ret = REG_NOERROR;
- free_return:
-  re_free (sifted_states);
-  re_free (lim_states);
-  return ret;
-}
-
-/* Acquire an initial state and return it.
-   We must select appropriate initial state depending on the context,
-   since initial states may have constraints like "\<", "^", etc..  */
-
-static inline re_dfastate_t *
-__attribute ((always_inline)) internal_function
-acquire_init_state_context (reg_errcode_t *err, const re_match_context_t *mctx,
-			    Idx idx)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  if (dfa->init_state->has_constraint)
-    {
-      unsigned int context;
-      context = re_string_context_at (&mctx->input, idx - 1, mctx->eflags);
-      if (IS_WORD_CONTEXT (context))
-	return dfa->init_state_word;
-      else if (IS_ORDINARY_CONTEXT (context))
-	return dfa->init_state;
-      else if (IS_BEGBUF_CONTEXT (context) && IS_NEWLINE_CONTEXT (context))
-	return dfa->init_state_begbuf;
-      else if (IS_NEWLINE_CONTEXT (context))
-	return dfa->init_state_nl;
-      else if (IS_BEGBUF_CONTEXT (context))
-	{
-	  /* It is relatively rare case, then calculate on demand.  */
-	  return re_acquire_state_context (err, dfa,
-					   dfa->init_state->entrance_nodes,
-					   context);
-	}
-      else
-	/* Must not happen?  */
-	return dfa->init_state;
-    }
-  else
-    return dfa->init_state;
-}
-
-/* Check whether the regular expression match input string INPUT or not,
-   and return the index where the matching end.  Return REG_MISSING if
-   there is no match, and return REG_ERROR in case of an error.
-   FL_LONGEST_MATCH means we want the POSIX longest matching.
-   If P_MATCH_FIRST is not NULL, and the match fails, it is set to the
-   next place where we may want to try matching.
-   Note that the matcher assume that the maching starts from the current
-   index of the buffer.  */
-
-static Idx
-internal_function
-check_matching (re_match_context_t *mctx, bool fl_longest_match,
-		Idx *p_match_first)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  reg_errcode_t err;
-  Idx match = 0;
-  Idx match_last = REG_MISSING;
-  Idx cur_str_idx = re_string_cur_idx (&mctx->input);
-  re_dfastate_t *cur_state;
-  bool at_init_state = p_match_first != NULL;
-  Idx next_start_idx = cur_str_idx;
-
-  err = REG_NOERROR;
-  cur_state = acquire_init_state_context (&err, mctx, cur_str_idx);
-  /* An initial state must not be NULL (invalid).  */
-  if (BE (cur_state == NULL, 0))
-    {
-      assert (err == REG_ESPACE);
-      return REG_ERROR;
-    }
-
-  if (mctx->state_log != NULL)
-    {
-      mctx->state_log[cur_str_idx] = cur_state;
-
-      /* Check OP_OPEN_SUBEXP in the initial state in case that we use them
-	 later.  E.g. Processing back references.  */
-      if (BE (dfa->nbackref, 0))
-	{
-	  at_init_state = false;
-	  err = check_subexp_matching_top (mctx, &cur_state->nodes, 0);
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-
-	  if (cur_state->has_backref)
-	    {
-	      err = transit_state_bkref (mctx, &cur_state->nodes);
-	      if (BE (err != REG_NOERROR, 0))
-	        return err;
-	    }
-	}
-    }
-
-  /* If the RE accepts NULL string.  */
-  if (BE (cur_state->halt, 0))
-    {
-      if (!cur_state->has_constraint
-	  || check_halt_state_context (mctx, cur_state, cur_str_idx))
-	{
-	  if (!fl_longest_match)
-	    return cur_str_idx;
-	  else
-	    {
-	      match_last = cur_str_idx;
-	      match = 1;
-	    }
-	}
-    }
-
-  while (!re_string_eoi (&mctx->input))
-    {
-      re_dfastate_t *old_state = cur_state;
-      Idx next_char_idx = re_string_cur_idx (&mctx->input) + 1;
-
-      if (BE (next_char_idx >= mctx->input.bufs_len, 0)
-          || (BE (next_char_idx >= mctx->input.valid_len, 0)
-              && mctx->input.valid_len < mctx->input.len))
-        {
-          err = extend_buffers (mctx);
-          if (BE (err != REG_NOERROR, 0))
-	    {
-	      assert (err == REG_ESPACE);
-	      return REG_ERROR;
-	    }
-        }
-
-      cur_state = transit_state (&err, mctx, cur_state);
-      if (mctx->state_log != NULL)
-	cur_state = merge_state_with_log (&err, mctx, cur_state);
-
-      if (cur_state == NULL)
-	{
-	  /* Reached the invalid state or an error.  Try to recover a valid
-	     state using the state log, if available and if we have not
-	     already found a valid (even if not the longest) match.  */
-	  if (BE (err != REG_NOERROR, 0))
-	    return REG_ERROR;
-
-	  if (mctx->state_log == NULL
-	      || (match && !fl_longest_match)
-	      || (cur_state = find_recover_state (&err, mctx)) == NULL)
-	    break;
-	}
-
-      if (BE (at_init_state, 0))
-	{
-	  if (old_state == cur_state)
-	    next_start_idx = next_char_idx;
-	  else
-	    at_init_state = false;
-	}
-
-      if (cur_state->halt)
-	{
-	  /* Reached a halt state.
-	     Check the halt state can satisfy the current context.  */
-	  if (!cur_state->has_constraint
-	      || check_halt_state_context (mctx, cur_state,
-					   re_string_cur_idx (&mctx->input)))
-	    {
-	      /* We found an appropriate halt state.  */
-	      match_last = re_string_cur_idx (&mctx->input);
-	      match = 1;
-
-	      /* We found a match, do not modify match_first below.  */
-	      p_match_first = NULL;
-	      if (!fl_longest_match)
-		break;
-	    }
-	}
-    }
-
-  if (p_match_first)
-    *p_match_first += next_start_idx;
-
-  return match_last;
-}
-
-/* Check NODE match the current context.  */
-
-static bool
-internal_function
-check_halt_node_context (const re_dfa_t *dfa, Idx node, unsigned int context)
-{
-  re_token_type_t type = dfa->nodes[node].type;
-  unsigned int constraint = dfa->nodes[node].constraint;
-  if (type != END_OF_RE)
-    return false;
-  if (!constraint)
-    return true;
-  if (NOT_SATISFY_NEXT_CONSTRAINT (constraint, context))
-    return false;
-  return true;
-}
-
-/* Check the halt state STATE match the current context.
-   Return 0 if not match, if the node, STATE has, is a halt node and
-   match the context, return the node.  */
-
-static Idx
-internal_function
-check_halt_state_context (const re_match_context_t *mctx,
-			  const re_dfastate_t *state, Idx idx)
-{
-  Idx i;
-  unsigned int context;
-#ifdef DEBUG
-  assert (state->halt);
-#endif
-  context = re_string_context_at (&mctx->input, idx, mctx->eflags);
-  for (i = 0; i < state->nodes.nelem; ++i)
-    if (check_halt_node_context (mctx->dfa, state->nodes.elems[i], context))
-      return state->nodes.elems[i];
-  return 0;
-}
-
-/* Compute the next node to which "NFA" transit from NODE("NFA" is a NFA
-   corresponding to the DFA).
-   Return the destination node, and update EPS_VIA_NODES;
-   return REG_MISSING in case of errors.  */
-
-static Idx
-internal_function
-proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
-		   Idx *pidx, Idx node, re_node_set *eps_via_nodes,
-		   struct re_fail_stack_t *fs)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  Idx i;
-  bool ok;
-  if (IS_EPSILON_NODE (dfa->nodes[node].type))
-    {
-      re_node_set *cur_nodes = &mctx->state_log[*pidx]->nodes;
-      re_node_set *edests = &dfa->edests[node];
-      Idx dest_node;
-      ok = re_node_set_insert (eps_via_nodes, node);
-      if (BE (! ok, 0))
-	return REG_ERROR;
-      /* Pick up a valid destination, or return REG_MISSING if none
-	 is found.  */
-      for (dest_node = REG_MISSING, i = 0; i < edests->nelem; ++i)
-	{
-	  Idx candidate = edests->elems[i];
-	  if (!re_node_set_contains (cur_nodes, candidate))
-	    continue;
-          if (dest_node == REG_MISSING)
-	    dest_node = candidate;
-
-          else
-	    {
-	      /* In order to avoid infinite loop like "(a*)*", return the second
-	         epsilon-transition if the first was already considered.  */
-	      if (re_node_set_contains (eps_via_nodes, dest_node))
-	        return candidate;
-
-	      /* Otherwise, push the second epsilon-transition on the fail stack.  */
-	      else if (fs != NULL
-		       && push_fail_stack (fs, *pidx, candidate, nregs, regs,
-				           eps_via_nodes))
-		return REG_ERROR;
-
-	      /* We know we are going to exit.  */
-	      break;
-	    }
-	}
-      return dest_node;
-    }
-  else
-    {
-      Idx naccepted = 0;
-      re_token_type_t type = dfa->nodes[node].type;
-
-#ifdef RE_ENABLE_I18N
-      if (dfa->nodes[node].accept_mb)
-	naccepted = check_node_accept_bytes (dfa, node, &mctx->input, *pidx);
-      else
-#endif /* RE_ENABLE_I18N */
-      if (type == OP_BACK_REF)
-	{
-	  Idx subexp_idx = dfa->nodes[node].opr.idx + 1;
-	  naccepted = regs[subexp_idx].rm_eo - regs[subexp_idx].rm_so;
-	  if (fs != NULL)
-	    {
-	      if (regs[subexp_idx].rm_so == -1 || regs[subexp_idx].rm_eo == -1)
-		return REG_MISSING;
-	      else if (naccepted)
-		{
-		  char *buf = (char *) re_string_get_buffer (&mctx->input);
-		  if (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
-			      naccepted) != 0)
-		    return REG_MISSING;
-		}
-	    }
-
-	  if (naccepted == 0)
-	    {
-	      Idx dest_node;
-	      ok = re_node_set_insert (eps_via_nodes, node);
-	      if (BE (! ok, 0))
-		return REG_ERROR;
-	      dest_node = dfa->edests[node].elems[0];
-	      if (re_node_set_contains (&mctx->state_log[*pidx]->nodes,
-					dest_node))
-		return dest_node;
-	    }
-	}
-
-      if (naccepted != 0
-	  || check_node_accept (mctx, dfa->nodes + node, *pidx))
-	{
-	  Idx dest_node = dfa->nexts[node];
-	  *pidx = (naccepted == 0) ? *pidx + 1 : *pidx + naccepted;
-	  if (fs && (*pidx > mctx->match_last || mctx->state_log[*pidx] == NULL
-		     || !re_node_set_contains (&mctx->state_log[*pidx]->nodes,
-					       dest_node)))
-	    return REG_MISSING;
-	  re_node_set_empty (eps_via_nodes);
-	  return dest_node;
-	}
-    }
-  return REG_MISSING;
-}
-
-static reg_errcode_t
-internal_function
-push_fail_stack (struct re_fail_stack_t *fs, Idx str_idx, Idx dest_node,
-		 Idx nregs, regmatch_t *regs, re_node_set *eps_via_nodes)
-{
-  reg_errcode_t err;
-  Idx num = fs->num++;
-  if (fs->num == fs->alloc)
-    {
-      struct re_fail_stack_ent_t *new_array;
-      new_array = realloc (fs->stack, (sizeof (struct re_fail_stack_ent_t)
-				       * fs->alloc * 2));
-      if (new_array == NULL)
-	return REG_ESPACE;
-      fs->alloc *= 2;
-      fs->stack = new_array;
-    }
-  fs->stack[num].idx = str_idx;
-  fs->stack[num].node = dest_node;
-  fs->stack[num].regs = re_malloc (regmatch_t, nregs);
-  if (fs->stack[num].regs == NULL)
-    return REG_ESPACE;
-  memcpy (fs->stack[num].regs, regs, sizeof (regmatch_t) * nregs);
-  err = re_node_set_init_copy (&fs->stack[num].eps_via_nodes, eps_via_nodes);
-  return err;
-}
-
-static Idx
-internal_function
-pop_fail_stack (struct re_fail_stack_t *fs, Idx *pidx, Idx nregs,
-		regmatch_t *regs, re_node_set *eps_via_nodes)
-{
-  Idx num = --fs->num;
-  assert (REG_VALID_INDEX (num));
-  *pidx = fs->stack[num].idx;
-  memcpy (regs, fs->stack[num].regs, sizeof (regmatch_t) * nregs);
-  re_node_set_free (eps_via_nodes);
-  re_free (fs->stack[num].regs);
-  *eps_via_nodes = fs->stack[num].eps_via_nodes;
-  return fs->stack[num].node;
-}
-
-/* Set the positions where the subexpressions are starts/ends to registers
-   PMATCH.
-   Note: We assume that pmatch[0] is already set, and
-   pmatch[i].rm_so == pmatch[i].rm_eo == -1 for 0 < i < nmatch.  */
-
-static reg_errcode_t
-internal_function
-set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
-	  regmatch_t *pmatch, bool fl_backtrack)
-{
-  const re_dfa_t *dfa = (const re_dfa_t *) preg->buffer;
-  Idx idx, cur_node;
-  re_node_set eps_via_nodes;
-  struct re_fail_stack_t *fs;
-  struct re_fail_stack_t fs_body = { 0, 2, NULL };
-  regmatch_t *prev_idx_match;
-  bool prev_idx_match_malloced = false;
-
-#ifdef DEBUG
-  assert (nmatch > 1);
-  assert (mctx->state_log != NULL);
-#endif
-  if (fl_backtrack)
-    {
-      fs = &fs_body;
-      fs->stack = re_malloc (struct re_fail_stack_ent_t, fs->alloc);
-      if (fs->stack == NULL)
-	return REG_ESPACE;
-    }
-  else
-    fs = NULL;
-
-  cur_node = dfa->init_node;
-  re_node_set_init_empty (&eps_via_nodes);
-
-  if (__libc_use_alloca (nmatch * sizeof (regmatch_t)))
-    prev_idx_match = (regmatch_t *) alloca (nmatch * sizeof (regmatch_t));
-  else
-    {
-      prev_idx_match = re_malloc (regmatch_t, nmatch);
-      if (prev_idx_match == NULL)
-	{
-	  free_fail_stack_return (fs);
-	  return REG_ESPACE;
-	}
-      prev_idx_match_malloced = true;
-    }
-  memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
-
-  for (idx = pmatch[0].rm_so; idx <= pmatch[0].rm_eo ;)
-    {
-      update_regs (dfa, pmatch, prev_idx_match, cur_node, idx, nmatch);
-
-      if (idx == pmatch[0].rm_eo && cur_node == mctx->last_node)
-	{
-	  Idx reg_idx;
-	  if (fs)
-	    {
-	      for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
-		if (pmatch[reg_idx].rm_so > -1 && pmatch[reg_idx].rm_eo == -1)
-		  break;
-	      if (reg_idx == nmatch)
-		{
-		  re_node_set_free (&eps_via_nodes);
-		  if (prev_idx_match_malloced)
-		    re_free (prev_idx_match);
-		  return free_fail_stack_return (fs);
-		}
-	      cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
-					 &eps_via_nodes);
-	    }
-	  else
-	    {
-	      re_node_set_free (&eps_via_nodes);
-	      if (prev_idx_match_malloced)
-		re_free (prev_idx_match);
-	      return REG_NOERROR;
-	    }
-	}
-
-      /* Proceed to next node.  */
-      cur_node = proceed_next_node (mctx, nmatch, pmatch, &idx, cur_node,
-				    &eps_via_nodes, fs);
-
-      if (BE (! REG_VALID_INDEX (cur_node), 0))
-	{
-	  if (BE (cur_node == REG_ERROR, 0))
-	    {
-	      re_node_set_free (&eps_via_nodes);
-	      if (prev_idx_match_malloced)
-		re_free (prev_idx_match);
-	      free_fail_stack_return (fs);
-	      return REG_ESPACE;
-	    }
-	  if (fs)
-	    cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
-				       &eps_via_nodes);
-	  else
-	    {
-	      re_node_set_free (&eps_via_nodes);
-	      if (prev_idx_match_malloced)
-		re_free (prev_idx_match);
-	      return REG_NOMATCH;
-	    }
-	}
-    }
-  re_node_set_free (&eps_via_nodes);
-  if (prev_idx_match_malloced)
-    re_free (prev_idx_match);
-  return free_fail_stack_return (fs);
-}
-
-static reg_errcode_t
-internal_function
-free_fail_stack_return (struct re_fail_stack_t *fs)
-{
-  if (fs)
-    {
-      Idx fs_idx;
-      for (fs_idx = 0; fs_idx < fs->num; ++fs_idx)
-	{
-	  re_node_set_free (&fs->stack[fs_idx].eps_via_nodes);
-	  re_free (fs->stack[fs_idx].regs);
-	}
-      re_free (fs->stack);
-    }
-  return REG_NOERROR;
-}
-
-static void
-internal_function
-update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
-	     regmatch_t *prev_idx_match, Idx cur_node, Idx cur_idx, Idx nmatch)
-{
-  int type = dfa->nodes[cur_node].type;
-  if (type == OP_OPEN_SUBEXP)
-    {
-      Idx reg_num = dfa->nodes[cur_node].opr.idx + 1;
-
-      /* We are at the first node of this sub expression.  */
-      if (reg_num < nmatch)
-	{
-	  pmatch[reg_num].rm_so = cur_idx;
-	  pmatch[reg_num].rm_eo = -1;
-	}
-    }
-  else if (type == OP_CLOSE_SUBEXP)
-    {
-      Idx reg_num = dfa->nodes[cur_node].opr.idx + 1;
-      if (reg_num < nmatch)
-	{
-	  /* We are at the last node of this sub expression.  */
-	  if (pmatch[reg_num].rm_so < cur_idx)
-	    {
-	      pmatch[reg_num].rm_eo = cur_idx;
-	      /* This is a non-empty match or we are not inside an optional
-		 subexpression.  Accept this right away.  */
-	      memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
-	    }
-	  else
-	    {
-	      if (dfa->nodes[cur_node].opt_subexp
-		  && prev_idx_match[reg_num].rm_so != -1)
-		/* We transited through an empty match for an optional
-		   subexpression, like (a?)*, and this is not the subexp's
-		   first match.  Copy back the old content of the registers
-		   so that matches of an inner subexpression are undone as
-		   well, like in ((a?))*.  */
-		memcpy (pmatch, prev_idx_match, sizeof (regmatch_t) * nmatch);
-	      else
-		/* We completed a subexpression, but it may be part of
-		   an optional one, so do not update PREV_IDX_MATCH.  */
-		pmatch[reg_num].rm_eo = cur_idx;
-	    }
-	}
-    }
-}
-
-/* This function checks the STATE_LOG from the SCTX->last_str_idx to 0
-   and sift the nodes in each states according to the following rules.
-   Updated state_log will be wrote to STATE_LOG.
-
-   Rules: We throw away the Node `a' in the STATE_LOG[STR_IDX] if...
-     1. When STR_IDX == MATCH_LAST(the last index in the state_log):
-	If `a' isn't the LAST_NODE and `a' can't epsilon transit to
-	the LAST_NODE, we throw away the node `a'.
-     2. When 0 <= STR_IDX < MATCH_LAST and `a' accepts
-	string `s' and transit to `b':
-	i. If 'b' isn't in the STATE_LOG[STR_IDX+strlen('s')], we throw
-	   away the node `a'.
-	ii. If 'b' is in the STATE_LOG[STR_IDX+strlen('s')] but 'b' is
-	    thrown away, we throw away the node `a'.
-     3. When 0 <= STR_IDX < MATCH_LAST and 'a' epsilon transit to 'b':
-	i. If 'b' isn't in the STATE_LOG[STR_IDX], we throw away the
-	   node `a'.
-	ii. If 'b' is in the STATE_LOG[STR_IDX] but 'b' is thrown away,
-	    we throw away the node `a'.  */
-
-#define STATE_NODE_CONTAINS(state,node) \
-  ((state) != NULL && re_node_set_contains (&(state)->nodes, node))
-
-static reg_errcode_t
-internal_function
-sift_states_backward (const re_match_context_t *mctx, re_sift_context_t *sctx)
-{
-  reg_errcode_t err;
-  int null_cnt = 0;
-  Idx str_idx = sctx->last_str_idx;
-  re_node_set cur_dest;
-
-#ifdef DEBUG
-  assert (mctx->state_log != NULL && mctx->state_log[str_idx] != NULL);
-#endif
-
-  /* Build sifted state_log[str_idx].  It has the nodes which can epsilon
-     transit to the last_node and the last_node itself.  */
-  err = re_node_set_init_1 (&cur_dest, sctx->last_node);
-  if (BE (err != REG_NOERROR, 0))
-    return err;
-  err = update_cur_sifted_state (mctx, sctx, str_idx, &cur_dest);
-  if (BE (err != REG_NOERROR, 0))
-    goto free_return;
-
-  /* Then check each states in the state_log.  */
-  while (str_idx > 0)
-    {
-      /* Update counters.  */
-      null_cnt = (sctx->sifted_states[str_idx] == NULL) ? null_cnt + 1 : 0;
-      if (null_cnt > mctx->max_mb_elem_len)
-	{
-	  memset (sctx->sifted_states, '\0',
-		  sizeof (re_dfastate_t *) * str_idx);
-	  re_node_set_free (&cur_dest);
-	  return REG_NOERROR;
-	}
-      re_node_set_empty (&cur_dest);
-      --str_idx;
-
-      if (mctx->state_log[str_idx])
-	{
-	  err = build_sifted_states (mctx, sctx, str_idx, &cur_dest);
-          if (BE (err != REG_NOERROR, 0))
-	    goto free_return;
-	}
-
-      /* Add all the nodes which satisfy the following conditions:
-	 - It can epsilon transit to a node in CUR_DEST.
-	 - It is in CUR_SRC.
-	 And update state_log.  */
-      err = update_cur_sifted_state (mctx, sctx, str_idx, &cur_dest);
-      if (BE (err != REG_NOERROR, 0))
-	goto free_return;
-    }
-  err = REG_NOERROR;
- free_return:
-  re_node_set_free (&cur_dest);
-  return err;
-}
-
-static reg_errcode_t
-internal_function
-build_sifted_states (const re_match_context_t *mctx, re_sift_context_t *sctx,
-		     Idx str_idx, re_node_set *cur_dest)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  const re_node_set *cur_src = &mctx->state_log[str_idx]->non_eps_nodes;
-  Idx i;
-
-  /* Then build the next sifted state.
-     We build the next sifted state on `cur_dest', and update
-     `sifted_states[str_idx]' with `cur_dest'.
-     Note:
-     `cur_dest' is the sifted state from `state_log[str_idx + 1]'.
-     `cur_src' points the node_set of the old `state_log[str_idx]'
-     (with the epsilon nodes pre-filtered out).  */
-  for (i = 0; i < cur_src->nelem; i++)
-    {
-      Idx prev_node = cur_src->elems[i];
-      int naccepted = 0;
-      bool ok;
-
-#ifdef DEBUG
-      re_token_type_t type = dfa->nodes[prev_node].type;
-      assert (!IS_EPSILON_NODE (type));
-#endif
-#ifdef RE_ENABLE_I18N
-      /* If the node may accept `multi byte'.  */
-      if (dfa->nodes[prev_node].accept_mb)
-	naccepted = sift_states_iter_mb (mctx, sctx, prev_node,
-					 str_idx, sctx->last_str_idx);
-#endif /* RE_ENABLE_I18N */
-
-      /* We don't check backreferences here.
-	 See update_cur_sifted_state().  */
-      if (!naccepted
-	  && check_node_accept (mctx, dfa->nodes + prev_node, str_idx)
-	  && STATE_NODE_CONTAINS (sctx->sifted_states[str_idx + 1],
-				  dfa->nexts[prev_node]))
-	naccepted = 1;
-
-      if (naccepted == 0)
-	continue;
-
-      if (sctx->limits.nelem)
-	{
-	  Idx to_idx = str_idx + naccepted;
-	  if (check_dst_limits (mctx, &sctx->limits,
-				dfa->nexts[prev_node], to_idx,
-				prev_node, str_idx))
-	    continue;
-	}
-      ok = re_node_set_insert (cur_dest, prev_node);
-      if (BE (! ok, 0))
-	return REG_ESPACE;
-    }
-
-  return REG_NOERROR;
-}
-
-/* Helper functions.  */
-
-static reg_errcode_t
-internal_function
-clean_state_log_if_needed (re_match_context_t *mctx, Idx next_state_log_idx)
-{
-  Idx top = mctx->state_log_top;
-
-  if (next_state_log_idx >= mctx->input.bufs_len
-      || (next_state_log_idx >= mctx->input.valid_len
-	  && mctx->input.valid_len < mctx->input.len))
-    {
-      reg_errcode_t err;
-      err = extend_buffers (mctx);
-      if (BE (err != REG_NOERROR, 0))
-	return err;
-    }
-
-  if (top < next_state_log_idx)
-    {
-      memset (mctx->state_log + top + 1, '\0',
-	      sizeof (re_dfastate_t *) * (next_state_log_idx - top));
-      mctx->state_log_top = next_state_log_idx;
-    }
-  return REG_NOERROR;
-}
-
-static reg_errcode_t
-internal_function
-merge_state_array (const re_dfa_t *dfa, re_dfastate_t **dst,
-		   re_dfastate_t **src, Idx num)
-{
-  Idx st_idx;
-  reg_errcode_t err;
-  for (st_idx = 0; st_idx < num; ++st_idx)
-    {
-      if (dst[st_idx] == NULL)
-	dst[st_idx] = src[st_idx];
-      else if (src[st_idx] != NULL)
-	{
-	  re_node_set merged_set;
-	  err = re_node_set_init_union (&merged_set, &dst[st_idx]->nodes,
-					&src[st_idx]->nodes);
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-	  dst[st_idx] = re_acquire_state (&err, dfa, &merged_set);
-	  re_node_set_free (&merged_set);
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-	}
-    }
-  return REG_NOERROR;
-}
-
-static reg_errcode_t
-internal_function
-update_cur_sifted_state (const re_match_context_t *mctx,
-			 re_sift_context_t *sctx, Idx str_idx,
-			 re_node_set *dest_nodes)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  reg_errcode_t err = REG_NOERROR;
-  const re_node_set *candidates;
-  candidates = ((mctx->state_log[str_idx] == NULL) ? NULL
-		: &mctx->state_log[str_idx]->nodes);
-
-  if (dest_nodes->nelem == 0)
-    sctx->sifted_states[str_idx] = NULL;
-  else
-    {
-      if (candidates)
-	{
-	  /* At first, add the nodes which can epsilon transit to a node in
-	     DEST_NODE.  */
-	  err = add_epsilon_src_nodes (dfa, dest_nodes, candidates);
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-
-	  /* Then, check the limitations in the current sift_context.  */
-	  if (sctx->limits.nelem)
-	    {
-	      err = check_subexp_limits (dfa, dest_nodes, candidates, &sctx->limits,
-					 mctx->bkref_ents, str_idx);
-	      if (BE (err != REG_NOERROR, 0))
-		return err;
-	    }
-	}
-
-      sctx->sifted_states[str_idx] = re_acquire_state (&err, dfa, dest_nodes);
-      if (BE (err != REG_NOERROR, 0))
-	return err;
-    }
-
-  if (candidates && mctx->state_log[str_idx]->has_backref)
-    {
-      err = sift_states_bkref (mctx, sctx, str_idx, candidates);
-      if (BE (err != REG_NOERROR, 0))
-	return err;
-    }
-  return REG_NOERROR;
-}
-
-static reg_errcode_t
-internal_function
-add_epsilon_src_nodes (const re_dfa_t *dfa, re_node_set *dest_nodes,
-		       const re_node_set *candidates)
-{
-  reg_errcode_t err = REG_NOERROR;
-  Idx i;
-
-  re_dfastate_t *state = re_acquire_state (&err, dfa, dest_nodes);
-  if (BE (err != REG_NOERROR, 0))
-    return err;
-
-  if (!state->inveclosure.alloc)
-    {
-      err = re_node_set_alloc (&state->inveclosure, dest_nodes->nelem);
-      if (BE (err != REG_NOERROR, 0))
-        return REG_ESPACE;
-      for (i = 0; i < dest_nodes->nelem; i++)
-        re_node_set_merge (&state->inveclosure,
-			   dfa->inveclosures + dest_nodes->elems[i]);
-    }
-  return re_node_set_add_intersect (dest_nodes, candidates,
-				    &state->inveclosure);
-}
-
-static reg_errcode_t
-internal_function
-sub_epsilon_src_nodes (const re_dfa_t *dfa, Idx node, re_node_set *dest_nodes,
-		       const re_node_set *candidates)
-{
-    Idx ecl_idx;
-    reg_errcode_t err;
-    re_node_set *inv_eclosure = dfa->inveclosures + node;
-    re_node_set except_nodes;
-    re_node_set_init_empty (&except_nodes);
-    for (ecl_idx = 0; ecl_idx < inv_eclosure->nelem; ++ecl_idx)
-      {
-	Idx cur_node = inv_eclosure->elems[ecl_idx];
-	if (cur_node == node)
-	  continue;
-	if (IS_EPSILON_NODE (dfa->nodes[cur_node].type))
-	  {
-	    Idx edst1 = dfa->edests[cur_node].elems[0];
-	    Idx edst2 = ((dfa->edests[cur_node].nelem > 1)
-			 ? dfa->edests[cur_node].elems[1] : REG_MISSING);
-	    if ((!re_node_set_contains (inv_eclosure, edst1)
-		 && re_node_set_contains (dest_nodes, edst1))
-		|| (REG_VALID_NONZERO_INDEX (edst2)
-		    && !re_node_set_contains (inv_eclosure, edst2)
-		    && re_node_set_contains (dest_nodes, edst2)))
-	      {
-		err = re_node_set_add_intersect (&except_nodes, candidates,
-						 dfa->inveclosures + cur_node);
-		if (BE (err != REG_NOERROR, 0))
-		  {
-		    re_node_set_free (&except_nodes);
-		    return err;
-		  }
-	      }
-	  }
-      }
-    for (ecl_idx = 0; ecl_idx < inv_eclosure->nelem; ++ecl_idx)
-      {
-	Idx cur_node = inv_eclosure->elems[ecl_idx];
-	if (!re_node_set_contains (&except_nodes, cur_node))
-	  {
-	    Idx idx = re_node_set_contains (dest_nodes, cur_node) - 1;
-	    re_node_set_remove_at (dest_nodes, idx);
-	  }
-      }
-    re_node_set_free (&except_nodes);
-    return REG_NOERROR;
-}
-
-static bool
-internal_function
-check_dst_limits (const re_match_context_t *mctx, const re_node_set *limits,
-		  Idx dst_node, Idx dst_idx, Idx src_node, Idx src_idx)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  Idx lim_idx, src_pos, dst_pos;
-
-  Idx dst_bkref_idx = search_cur_bkref_entry (mctx, dst_idx);
-  Idx src_bkref_idx = search_cur_bkref_entry (mctx, src_idx);
-  for (lim_idx = 0; lim_idx < limits->nelem; ++lim_idx)
-    {
-      Idx subexp_idx;
-      struct re_backref_cache_entry *ent;
-      ent = mctx->bkref_ents + limits->elems[lim_idx];
-      subexp_idx = dfa->nodes[ent->node].opr.idx;
-
-      dst_pos = check_dst_limits_calc_pos (mctx, limits->elems[lim_idx],
-					   subexp_idx, dst_node, dst_idx,
-					   dst_bkref_idx);
-      src_pos = check_dst_limits_calc_pos (mctx, limits->elems[lim_idx],
-					   subexp_idx, src_node, src_idx,
-					   src_bkref_idx);
-
-      /* In case of:
-	 <src> <dst> ( <subexp> )
-	 ( <subexp> ) <src> <dst>
-	 ( <subexp1> <src> <subexp2> <dst> <subexp3> )  */
-      if (src_pos == dst_pos)
-	continue; /* This is unrelated limitation.  */
-      else
-	return true;
-    }
-  return false;
-}
-
-static int
-internal_function
-check_dst_limits_calc_pos_1 (const re_match_context_t *mctx, int boundaries,
-			     Idx subexp_idx, Idx from_node, Idx bkref_idx)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  const re_node_set *eclosures = dfa->eclosures + from_node;
-  Idx node_idx;
-
-  /* Else, we are on the boundary: examine the nodes on the epsilon
-     closure.  */
-  for (node_idx = 0; node_idx < eclosures->nelem; ++node_idx)
-    {
-      Idx node = eclosures->elems[node_idx];
-      switch (dfa->nodes[node].type)
-	{
-	case OP_BACK_REF:
-	  if (bkref_idx != REG_MISSING)
-	    {
-	      struct re_backref_cache_entry *ent = mctx->bkref_ents + bkref_idx;
-	      do
-	        {
-		  Idx dst;
-		  int cpos;
-
-		  if (ent->node != node)
-		    continue;
-
-		  if (subexp_idx < BITSET_WORD_BITS
-		      && !(ent->eps_reachable_subexps_map
-			   & ((bitset_word_t) 1 << subexp_idx)))
-		    continue;
-
-		  /* Recurse trying to reach the OP_OPEN_SUBEXP and
-		     OP_CLOSE_SUBEXP cases below.  But, if the
-		     destination node is the same node as the source
-		     node, don't recurse because it would cause an
-		     infinite loop: a regex that exhibits this behavior
-		     is ()\1*\1*  */
-		  dst = dfa->edests[node].elems[0];
-		  if (dst == from_node)
-		    {
-		      if (boundaries & 1)
-		        return -1;
-		      else /* if (boundaries & 2) */
-		        return 0;
-		    }
-
-		  cpos =
-		    check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx,
-						 dst, bkref_idx);
-		  if (cpos == -1 /* && (boundaries & 1) */)
-		    return -1;
-		  if (cpos == 0 && (boundaries & 2))
-		    return 0;
-
-		  if (subexp_idx < BITSET_WORD_BITS)
-		    ent->eps_reachable_subexps_map
-		      &= ~((bitset_word_t) 1 << subexp_idx);
-	        }
-	      while (ent++->more);
-	    }
-	  break;
-
-	case OP_OPEN_SUBEXP:
-	  if ((boundaries & 1) && subexp_idx == dfa->nodes[node].opr.idx)
-	    return -1;
-	  break;
-
-	case OP_CLOSE_SUBEXP:
-	  if ((boundaries & 2) && subexp_idx == dfa->nodes[node].opr.idx)
-	    return 0;
-	  break;
-
-	default:
-	    break;
-	}
-    }
-
-  return (boundaries & 2) ? 1 : 0;
-}
-
-static int
-internal_function
-check_dst_limits_calc_pos (const re_match_context_t *mctx, Idx limit,
-			   Idx subexp_idx, Idx from_node, Idx str_idx,
-			   Idx bkref_idx)
-{
-  struct re_backref_cache_entry *lim = mctx->bkref_ents + limit;
-  int boundaries;
-
-  /* If we are outside the range of the subexpression, return -1 or 1.  */
-  if (str_idx < lim->subexp_from)
-    return -1;
-
-  if (lim->subexp_to < str_idx)
-    return 1;
-
-  /* If we are within the subexpression, return 0.  */
-  boundaries = (str_idx == lim->subexp_from);
-  boundaries |= (str_idx == lim->subexp_to) << 1;
-  if (boundaries == 0)
-    return 0;
-
-  /* Else, examine epsilon closure.  */
-  return check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx,
-				      from_node, bkref_idx);
-}
-
-/* Check the limitations of sub expressions LIMITS, and remove the nodes
-   which are against limitations from DEST_NODES. */
-
-static reg_errcode_t
-internal_function
-check_subexp_limits (const re_dfa_t *dfa, re_node_set *dest_nodes,
-		     const re_node_set *candidates, re_node_set *limits,
-		     struct re_backref_cache_entry *bkref_ents, Idx str_idx)
-{
-  reg_errcode_t err;
-  Idx node_idx, lim_idx;
-
-  for (lim_idx = 0; lim_idx < limits->nelem; ++lim_idx)
-    {
-      Idx subexp_idx;
-      struct re_backref_cache_entry *ent;
-      ent = bkref_ents + limits->elems[lim_idx];
-
-      if (str_idx <= ent->subexp_from || ent->str_idx < str_idx)
-	continue; /* This is unrelated limitation.  */
-
-      subexp_idx = dfa->nodes[ent->node].opr.idx;
-      if (ent->subexp_to == str_idx)
-	{
-	  Idx ops_node = REG_MISSING;
-	  Idx cls_node = REG_MISSING;
-	  for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
-	    {
-	      Idx node = dest_nodes->elems[node_idx];
-	      re_token_type_t type = dfa->nodes[node].type;
-	      if (type == OP_OPEN_SUBEXP
-		  && subexp_idx == dfa->nodes[node].opr.idx)
-		ops_node = node;
-	      else if (type == OP_CLOSE_SUBEXP
-		       && subexp_idx == dfa->nodes[node].opr.idx)
-		cls_node = node;
-	    }
-
-	  /* Check the limitation of the open subexpression.  */
-	  /* Note that (ent->subexp_to = str_idx != ent->subexp_from).  */
-	  if (REG_VALID_INDEX (ops_node))
-	    {
-	      err = sub_epsilon_src_nodes (dfa, ops_node, dest_nodes,
-					   candidates);
-	      if (BE (err != REG_NOERROR, 0))
-		return err;
-	    }
-
-	  /* Check the limitation of the close subexpression.  */
-	  if (REG_VALID_INDEX (cls_node))
-	    for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
-	      {
-		Idx node = dest_nodes->elems[node_idx];
-		if (!re_node_set_contains (dfa->inveclosures + node,
-					   cls_node)
-		    && !re_node_set_contains (dfa->eclosures + node,
-					      cls_node))
-		  {
-		    /* It is against this limitation.
-		       Remove it form the current sifted state.  */
-		    err = sub_epsilon_src_nodes (dfa, node, dest_nodes,
-						 candidates);
-		    if (BE (err != REG_NOERROR, 0))
-		      return err;
-		    --node_idx;
-		  }
-	      }
-	}
-      else /* (ent->subexp_to != str_idx)  */
-	{
-	  for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
-	    {
-	      Idx node = dest_nodes->elems[node_idx];
-	      re_token_type_t type = dfa->nodes[node].type;
-	      if (type == OP_CLOSE_SUBEXP || type == OP_OPEN_SUBEXP)
-		{
-		  if (subexp_idx != dfa->nodes[node].opr.idx)
-		    continue;
-		  /* It is against this limitation.
-		     Remove it form the current sifted state.  */
-		  err = sub_epsilon_src_nodes (dfa, node, dest_nodes,
-					       candidates);
-		  if (BE (err != REG_NOERROR, 0))
-		    return err;
-		}
-	    }
-	}
-    }
-  return REG_NOERROR;
-}
-
-static reg_errcode_t
-internal_function
-sift_states_bkref (const re_match_context_t *mctx, re_sift_context_t *sctx,
-		   Idx str_idx, const re_node_set *candidates)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  reg_errcode_t err;
-  Idx node_idx, node;
-  re_sift_context_t local_sctx;
-  Idx first_idx = search_cur_bkref_entry (mctx, str_idx);
-
-  if (first_idx == REG_MISSING)
-    return REG_NOERROR;
-
-  local_sctx.sifted_states = NULL; /* Mark that it hasn't been initialized.  */
-
-  for (node_idx = 0; node_idx < candidates->nelem; ++node_idx)
-    {
-      Idx enabled_idx;
-      re_token_type_t type;
-      struct re_backref_cache_entry *entry;
-      node = candidates->elems[node_idx];
-      type = dfa->nodes[node].type;
-      /* Avoid infinite loop for the REs like "()\1+".  */
-      if (node == sctx->last_node && str_idx == sctx->last_str_idx)
-	continue;
-      if (type != OP_BACK_REF)
-	continue;
-
-      entry = mctx->bkref_ents + first_idx;
-      enabled_idx = first_idx;
-      do
-	{
-	  Idx subexp_len;
-	  Idx to_idx;
-	  Idx dst_node;
-	  bool ok;
-	  re_dfastate_t *cur_state;
-
-	  if (entry->node != node)
-	    continue;
-	  subexp_len = entry->subexp_to - entry->subexp_from;
-	  to_idx = str_idx + subexp_len;
-	  dst_node = (subexp_len ? dfa->nexts[node]
-		      : dfa->edests[node].elems[0]);
-
-	  if (to_idx > sctx->last_str_idx
-	      || sctx->sifted_states[to_idx] == NULL
-	      || !STATE_NODE_CONTAINS (sctx->sifted_states[to_idx], dst_node)
-	      || check_dst_limits (mctx, &sctx->limits, node,
-				   str_idx, dst_node, to_idx))
-	    continue;
-
-	  if (local_sctx.sifted_states == NULL)
-	    {
-	      local_sctx = *sctx;
-	      err = re_node_set_init_copy (&local_sctx.limits, &sctx->limits);
-	      if (BE (err != REG_NOERROR, 0))
-		goto free_return;
-	    }
-	  local_sctx.last_node = node;
-	  local_sctx.last_str_idx = str_idx;
-	  ok = re_node_set_insert (&local_sctx.limits, enabled_idx);
-	  if (BE (! ok, 0))
-	    {
-	      err = REG_ESPACE;
-	      goto free_return;
-	    }
-	  cur_state = local_sctx.sifted_states[str_idx];
-	  err = sift_states_backward (mctx, &local_sctx);
-	  if (BE (err != REG_NOERROR, 0))
-	    goto free_return;
-	  if (sctx->limited_states != NULL)
-	    {
-	      err = merge_state_array (dfa, sctx->limited_states,
-				       local_sctx.sifted_states,
-				       str_idx + 1);
-	      if (BE (err != REG_NOERROR, 0))
-		goto free_return;
-	    }
-	  local_sctx.sifted_states[str_idx] = cur_state;
-	  re_node_set_remove (&local_sctx.limits, enabled_idx);
-
-	  /* mctx->bkref_ents may have changed, reload the pointer.  */
-          entry = mctx->bkref_ents + enabled_idx;
-	}
-      while (enabled_idx++, entry++->more);
-    }
-  err = REG_NOERROR;
- free_return:
-  if (local_sctx.sifted_states != NULL)
-    {
-      re_node_set_free (&local_sctx.limits);
-    }
-
-  return err;
-}
-
-
-#ifdef RE_ENABLE_I18N
-static int
-internal_function
-sift_states_iter_mb (const re_match_context_t *mctx, re_sift_context_t *sctx,
-		     Idx node_idx, Idx str_idx, Idx max_str_idx)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  int naccepted;
-  /* Check the node can accept `multi byte'.  */
-  naccepted = check_node_accept_bytes (dfa, node_idx, &mctx->input, str_idx);
-  if (naccepted > 0 && str_idx + naccepted <= max_str_idx &&
-      !STATE_NODE_CONTAINS (sctx->sifted_states[str_idx + naccepted],
-			    dfa->nexts[node_idx]))
-    /* The node can't accept the `multi byte', or the
-       destination was already thrown away, then the node
-       could't accept the current input `multi byte'.   */
-    naccepted = 0;
-  /* Otherwise, it is sure that the node could accept
-     `naccepted' bytes input.  */
-  return naccepted;
-}
-#endif /* RE_ENABLE_I18N */
-
-
-/* Functions for state transition.  */
-
-/* Return the next state to which the current state STATE will transit by
-   accepting the current input byte, and update STATE_LOG if necessary.
-   If STATE can accept a multibyte char/collating element/back reference
-   update the destination of STATE_LOG.  */
-
-static re_dfastate_t *
-internal_function
-transit_state (reg_errcode_t *err, re_match_context_t *mctx,
-	       re_dfastate_t *state)
-{
-  re_dfastate_t **trtable;
-  unsigned char ch;
-
-#ifdef RE_ENABLE_I18N
-  /* If the current state can accept multibyte.  */
-  if (BE (state->accept_mb, 0))
-    {
-      *err = transit_state_mb (mctx, state);
-      if (BE (*err != REG_NOERROR, 0))
-	return NULL;
-    }
-#endif /* RE_ENABLE_I18N */
-
-  /* Then decide the next state with the single byte.  */
-#if 0
-  if (0)
-    /* don't use transition table  */
-    return transit_state_sb (err, mctx, state);
-#endif
-
-  /* Use transition table  */
-  ch = re_string_fetch_byte (&mctx->input);
-  for (;;)
-    {
-      trtable = state->trtable;
-      if (BE (trtable != NULL, 1))
-	return trtable[ch];
-
-      trtable = state->word_trtable;
-      if (BE (trtable != NULL, 1))
-        {
-	  unsigned int context;
-	  context
-	    = re_string_context_at (&mctx->input,
-				    re_string_cur_idx (&mctx->input) - 1,
-				    mctx->eflags);
-	  if (IS_WORD_CONTEXT (context))
-	    return trtable[ch + SBC_MAX];
-	  else
-	    return trtable[ch];
-	}
-
-      if (!build_trtable (mctx->dfa, state))
-	{
-	  *err = REG_ESPACE;
-	  return NULL;
-	}
-
-      /* Retry, we now have a transition table.  */
-    }
-}
-
-/* Update the state_log if we need */
-static re_dfastate_t *
-internal_function
-merge_state_with_log (reg_errcode_t *err, re_match_context_t *mctx,
-		      re_dfastate_t *next_state)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  Idx cur_idx = re_string_cur_idx (&mctx->input);
-
-  if (cur_idx > mctx->state_log_top)
-    {
-      mctx->state_log[cur_idx] = next_state;
-      mctx->state_log_top = cur_idx;
-    }
-  else if (mctx->state_log[cur_idx] == 0)
-    {
-      mctx->state_log[cur_idx] = next_state;
-    }
-  else
-    {
-      re_dfastate_t *pstate;
-      unsigned int context;
-      re_node_set next_nodes, *log_nodes, *table_nodes = NULL;
-      /* If (state_log[cur_idx] != 0), it implies that cur_idx is
-         the destination of a multibyte char/collating element/
-         back reference.  Then the next state is the union set of
-         these destinations and the results of the transition table.  */
-      pstate = mctx->state_log[cur_idx];
-      log_nodes = pstate->entrance_nodes;
-      if (next_state != NULL)
-        {
-          table_nodes = next_state->entrance_nodes;
-          *err = re_node_set_init_union (&next_nodes, table_nodes,
-					     log_nodes);
-          if (BE (*err != REG_NOERROR, 0))
-	    return NULL;
-        }
-      else
-        next_nodes = *log_nodes;
-      /* Note: We already add the nodes of the initial state,
-	 then we don't need to add them here.  */
-
-      context = re_string_context_at (&mctx->input,
-				      re_string_cur_idx (&mctx->input) - 1,
-				      mctx->eflags);
-      next_state = mctx->state_log[cur_idx]
-        = re_acquire_state_context (err, dfa, &next_nodes, context);
-      /* We don't need to check errors here, since the return value of
-         this function is next_state and ERR is already set.  */
-
-      if (table_nodes != NULL)
-        re_node_set_free (&next_nodes);
-    }
-
-  if (BE (dfa->nbackref, 0) && next_state != NULL)
-    {
-      /* Check OP_OPEN_SUBEXP in the current state in case that we use them
-	 later.  We must check them here, since the back references in the
-	 next state might use them.  */
-      *err = check_subexp_matching_top (mctx, &next_state->nodes,
-					cur_idx);
-      if (BE (*err != REG_NOERROR, 0))
-	return NULL;
-
-      /* If the next state has back references.  */
-      if (next_state->has_backref)
-	{
-	  *err = transit_state_bkref (mctx, &next_state->nodes);
-	  if (BE (*err != REG_NOERROR, 0))
-	    return NULL;
-	  next_state = mctx->state_log[cur_idx];
-	}
-    }
-
-  return next_state;
-}
-
-/* Skip bytes in the input that correspond to part of a
-   multi-byte match, then look in the log for a state
-   from which to restart matching.  */
-static re_dfastate_t *
-internal_function
-find_recover_state (reg_errcode_t *err, re_match_context_t *mctx)
-{
-  re_dfastate_t *cur_state;
-  do
-    {
-      Idx max = mctx->state_log_top;
-      Idx cur_str_idx = re_string_cur_idx (&mctx->input);
-
-      do
-	{
-          if (++cur_str_idx > max)
-            return NULL;
-          re_string_skip_bytes (&mctx->input, 1);
-	}
-      while (mctx->state_log[cur_str_idx] == NULL);
-
-      cur_state = merge_state_with_log (err, mctx, NULL);
-    }
-  while (*err == REG_NOERROR && cur_state == NULL);
-  return cur_state;
-}
-
-/* Helper functions for transit_state.  */
-
-/* From the node set CUR_NODES, pick up the nodes whose types are
-   OP_OPEN_SUBEXP and which have corresponding back references in the regular
-   expression. And register them to use them later for evaluating the
-   correspoding back references.  */
-
-static reg_errcode_t
-internal_function
-check_subexp_matching_top (re_match_context_t *mctx, re_node_set *cur_nodes,
-			   Idx str_idx)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  Idx node_idx;
-  reg_errcode_t err;
-
-  /* TODO: This isn't efficient.
-	   Because there might be more than one nodes whose types are
-	   OP_OPEN_SUBEXP and whose index is SUBEXP_IDX, we must check all
-	   nodes.
-	   E.g. RE: (a){2}  */
-  for (node_idx = 0; node_idx < cur_nodes->nelem; ++node_idx)
-    {
-      Idx node = cur_nodes->elems[node_idx];
-      if (dfa->nodes[node].type == OP_OPEN_SUBEXP
-	  && dfa->nodes[node].opr.idx < BITSET_WORD_BITS
-	  && (dfa->used_bkref_map
-	      & ((bitset_word_t) 1 << dfa->nodes[node].opr.idx)))
-	{
-	  err = match_ctx_add_subtop (mctx, node, str_idx);
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-	}
-    }
-  return REG_NOERROR;
-}
-
-#if 0
-/* Return the next state to which the current state STATE will transit by
-   accepting the current input byte.  */
-
-static re_dfastate_t *
-transit_state_sb (reg_errcode_t *err, re_match_context_t *mctx,
-		  re_dfastate_t *state)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  re_node_set next_nodes;
-  re_dfastate_t *next_state;
-  Idx node_cnt, cur_str_idx = re_string_cur_idx (&mctx->input);
-  unsigned int context;
-
-  *err = re_node_set_alloc (&next_nodes, state->nodes.nelem + 1);
-  if (BE (*err != REG_NOERROR, 0))
-    return NULL;
-  for (node_cnt = 0; node_cnt < state->nodes.nelem; ++node_cnt)
-    {
-      Idx cur_node = state->nodes.elems[node_cnt];
-      if (check_node_accept (mctx, dfa->nodes + cur_node, cur_str_idx))
-	{
-	  *err = re_node_set_merge (&next_nodes,
-				    dfa->eclosures + dfa->nexts[cur_node]);
-	  if (BE (*err != REG_NOERROR, 0))
-	    {
-	      re_node_set_free (&next_nodes);
-	      return NULL;
-	    }
-	}
-    }
-  context = re_string_context_at (&mctx->input, cur_str_idx, mctx->eflags);
-  next_state = re_acquire_state_context (err, dfa, &next_nodes, context);
-  /* We don't need to check errors here, since the return value of
-     this function is next_state and ERR is already set.  */
-
-  re_node_set_free (&next_nodes);
-  re_string_skip_bytes (&mctx->input, 1);
-  return next_state;
-}
-#endif
-
-#ifdef RE_ENABLE_I18N
-static reg_errcode_t
-internal_function
-transit_state_mb (re_match_context_t *mctx, re_dfastate_t *pstate)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  reg_errcode_t err;
-  Idx i;
-
-  for (i = 0; i < pstate->nodes.nelem; ++i)
-    {
-      re_node_set dest_nodes, *new_nodes;
-      Idx cur_node_idx = pstate->nodes.elems[i];
-      int naccepted;
-      Idx dest_idx;
-      unsigned int context;
-      re_dfastate_t *dest_state;
-
-      if (!dfa->nodes[cur_node_idx].accept_mb)
-        continue;
-
-      if (dfa->nodes[cur_node_idx].constraint)
-	{
-	  context = re_string_context_at (&mctx->input,
-					  re_string_cur_idx (&mctx->input),
-					  mctx->eflags);
-	  if (NOT_SATISFY_NEXT_CONSTRAINT (dfa->nodes[cur_node_idx].constraint,
-					   context))
-	    continue;
-	}
-
-      /* How many bytes the node can accept?  */
-      naccepted = check_node_accept_bytes (dfa, cur_node_idx, &mctx->input,
-					   re_string_cur_idx (&mctx->input));
-      if (naccepted == 0)
-	continue;
-
-      /* The node can accepts `naccepted' bytes.  */
-      dest_idx = re_string_cur_idx (&mctx->input) + naccepted;
-      mctx->max_mb_elem_len = ((mctx->max_mb_elem_len < naccepted) ? naccepted
-			       : mctx->max_mb_elem_len);
-      err = clean_state_log_if_needed (mctx, dest_idx);
-      if (BE (err != REG_NOERROR, 0))
-	return err;
-#ifdef DEBUG
-      assert (dfa->nexts[cur_node_idx] != REG_MISSING);
-#endif
-      new_nodes = dfa->eclosures + dfa->nexts[cur_node_idx];
-
-      dest_state = mctx->state_log[dest_idx];
-      if (dest_state == NULL)
-	dest_nodes = *new_nodes;
-      else
-	{
-	  err = re_node_set_init_union (&dest_nodes,
-					dest_state->entrance_nodes, new_nodes);
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-	}
-      context = re_string_context_at (&mctx->input, dest_idx - 1,
-				      mctx->eflags);
-      mctx->state_log[dest_idx]
-	= re_acquire_state_context (&err, dfa, &dest_nodes, context);
-      if (dest_state != NULL)
-	re_node_set_free (&dest_nodes);
-      if (BE (mctx->state_log[dest_idx] == NULL && err != REG_NOERROR, 0))
-	return err;
-    }
-  return REG_NOERROR;
-}
-#endif /* RE_ENABLE_I18N */
-
-static reg_errcode_t
-internal_function
-transit_state_bkref (re_match_context_t *mctx, const re_node_set *nodes)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  reg_errcode_t err;
-  Idx i;
-  Idx cur_str_idx = re_string_cur_idx (&mctx->input);
-
-  for (i = 0; i < nodes->nelem; ++i)
-    {
-      Idx dest_str_idx, prev_nelem, bkc_idx;
-      Idx node_idx = nodes->elems[i];
-      unsigned int context;
-      const re_token_t *node = dfa->nodes + node_idx;
-      re_node_set *new_dest_nodes;
-
-      /* Check whether `node' is a backreference or not.  */
-      if (node->type != OP_BACK_REF)
-	continue;
-
-      if (node->constraint)
-	{
-	  context = re_string_context_at (&mctx->input, cur_str_idx,
-					  mctx->eflags);
-	  if (NOT_SATISFY_NEXT_CONSTRAINT (node->constraint, context))
-	    continue;
-	}
-
-      /* `node' is a backreference.
-	 Check the substring which the substring matched.  */
-      bkc_idx = mctx->nbkref_ents;
-      err = get_subexp (mctx, node_idx, cur_str_idx);
-      if (BE (err != REG_NOERROR, 0))
-	goto free_return;
-
-      /* And add the epsilon closures (which is `new_dest_nodes') of
-	 the backreference to appropriate state_log.  */
-#ifdef DEBUG
-      assert (dfa->nexts[node_idx] != REG_MISSING);
-#endif
-      for (; bkc_idx < mctx->nbkref_ents; ++bkc_idx)
-	{
-	  Idx subexp_len;
-	  re_dfastate_t *dest_state;
-	  struct re_backref_cache_entry *bkref_ent;
-	  bkref_ent = mctx->bkref_ents + bkc_idx;
-	  if (bkref_ent->node != node_idx || bkref_ent->str_idx != cur_str_idx)
-	    continue;
-	  subexp_len = bkref_ent->subexp_to - bkref_ent->subexp_from;
-	  new_dest_nodes = (subexp_len == 0
-			    ? dfa->eclosures + dfa->edests[node_idx].elems[0]
-			    : dfa->eclosures + dfa->nexts[node_idx]);
-	  dest_str_idx = (cur_str_idx + bkref_ent->subexp_to
-			  - bkref_ent->subexp_from);
-	  context = re_string_context_at (&mctx->input, dest_str_idx - 1,
-					  mctx->eflags);
-	  dest_state = mctx->state_log[dest_str_idx];
-	  prev_nelem = ((mctx->state_log[cur_str_idx] == NULL) ? 0
-			: mctx->state_log[cur_str_idx]->nodes.nelem);
-	  /* Add `new_dest_node' to state_log.  */
-	  if (dest_state == NULL)
-	    {
-	      mctx->state_log[dest_str_idx]
-		= re_acquire_state_context (&err, dfa, new_dest_nodes,
-					    context);
-	      if (BE (mctx->state_log[dest_str_idx] == NULL
-		      && err != REG_NOERROR, 0))
-		goto free_return;
-	    }
-	  else
-	    {
-	      re_node_set dest_nodes;
-	      err = re_node_set_init_union (&dest_nodes,
-					    dest_state->entrance_nodes,
-					    new_dest_nodes);
-	      if (BE (err != REG_NOERROR, 0))
-		{
-		  re_node_set_free (&dest_nodes);
-		  goto free_return;
-		}
-	      mctx->state_log[dest_str_idx]
-		= re_acquire_state_context (&err, dfa, &dest_nodes, context);
-	      re_node_set_free (&dest_nodes);
-	      if (BE (mctx->state_log[dest_str_idx] == NULL
-		      && err != REG_NOERROR, 0))
-		goto free_return;
-	    }
-	  /* We need to check recursively if the backreference can epsilon
-	     transit.  */
-	  if (subexp_len == 0
-	      && mctx->state_log[cur_str_idx]->nodes.nelem > prev_nelem)
-	    {
-	      err = check_subexp_matching_top (mctx, new_dest_nodes,
-					       cur_str_idx);
-	      if (BE (err != REG_NOERROR, 0))
-		goto free_return;
-	      err = transit_state_bkref (mctx, new_dest_nodes);
-	      if (BE (err != REG_NOERROR, 0))
-		goto free_return;
-	    }
-	}
-    }
-  err = REG_NOERROR;
- free_return:
-  return err;
-}
-
-/* Enumerate all the candidates which the backreference BKREF_NODE can match
-   at BKREF_STR_IDX, and register them by match_ctx_add_entry().
-   Note that we might collect inappropriate candidates here.
-   However, the cost of checking them strictly here is too high, then we
-   delay these checking for prune_impossible_nodes().  */
-
-static reg_errcode_t
-internal_function
-get_subexp (re_match_context_t *mctx, Idx bkref_node, Idx bkref_str_idx)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  Idx subexp_num, sub_top_idx;
-  const char *buf = (const char *) re_string_get_buffer (&mctx->input);
-  /* Return if we have already checked BKREF_NODE at BKREF_STR_IDX.  */
-  Idx cache_idx = search_cur_bkref_entry (mctx, bkref_str_idx);
-  if (cache_idx != REG_MISSING)
-    {
-      const struct re_backref_cache_entry *entry
-	= mctx->bkref_ents + cache_idx;
-      do
-        if (entry->node == bkref_node)
-	  return REG_NOERROR; /* We already checked it.  */
-      while (entry++->more);
-    }
-
-  subexp_num = dfa->nodes[bkref_node].opr.idx;
-
-  /* For each sub expression  */
-  for (sub_top_idx = 0; sub_top_idx < mctx->nsub_tops; ++sub_top_idx)
-    {
-      reg_errcode_t err;
-      re_sub_match_top_t *sub_top = mctx->sub_tops[sub_top_idx];
-      re_sub_match_last_t *sub_last;
-      Idx sub_last_idx, sl_str, bkref_str_off;
-
-      if (dfa->nodes[sub_top->node].opr.idx != subexp_num)
-	continue; /* It isn't related.  */
-
-      sl_str = sub_top->str_idx;
-      bkref_str_off = bkref_str_idx;
-      /* At first, check the last node of sub expressions we already
-	 evaluated.  */
-      for (sub_last_idx = 0; sub_last_idx < sub_top->nlasts; ++sub_last_idx)
-	{
-	  regoff_t sl_str_diff;
-	  sub_last = sub_top->lasts[sub_last_idx];
-	  sl_str_diff = sub_last->str_idx - sl_str;
-	  /* The matched string by the sub expression match with the substring
-	     at the back reference?  */
-	  if (sl_str_diff > 0)
-	    {
-	      if (BE (bkref_str_off + sl_str_diff > mctx->input.valid_len, 0))
-		{
-		  /* Not enough chars for a successful match.  */
-		  if (bkref_str_off + sl_str_diff > mctx->input.len)
-		    break;
-
-		  err = clean_state_log_if_needed (mctx,
-						   bkref_str_off
-						   + sl_str_diff);
-		  if (BE (err != REG_NOERROR, 0))
-		    return err;
-		  buf = (const char *) re_string_get_buffer (&mctx->input);
-		}
-	      if (memcmp (buf + bkref_str_off, buf + sl_str, sl_str_diff) != 0)
-		/* We don't need to search this sub expression any more.  */
-		break;
-	    }
-	  bkref_str_off += sl_str_diff;
-	  sl_str += sl_str_diff;
-	  err = get_subexp_sub (mctx, sub_top, sub_last, bkref_node,
-				bkref_str_idx);
-
-	  /* Reload buf, since the preceding call might have reallocated
-	     the buffer.  */
-	  buf = (const char *) re_string_get_buffer (&mctx->input);
-
-	  if (err == REG_NOMATCH)
-	    continue;
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-	}
-
-      if (sub_last_idx < sub_top->nlasts)
-	continue;
-      if (sub_last_idx > 0)
-	++sl_str;
-      /* Then, search for the other last nodes of the sub expression.  */
-      for (; sl_str <= bkref_str_idx; ++sl_str)
-	{
-	  Idx cls_node;
-	  regoff_t sl_str_off;
-	  const re_node_set *nodes;
-	  sl_str_off = sl_str - sub_top->str_idx;
-	  /* The matched string by the sub expression match with the substring
-	     at the back reference?  */
-	  if (sl_str_off > 0)
-	    {
-	      if (BE (bkref_str_off >= mctx->input.valid_len, 0))
-		{
-		  /* If we are at the end of the input, we cannot match.  */
-		  if (bkref_str_off >= mctx->input.len)
-		    break;
-
-		  err = extend_buffers (mctx);
-		  if (BE (err != REG_NOERROR, 0))
-		    return err;
-
-		  buf = (const char *) re_string_get_buffer (&mctx->input);
-		}
-	      if (buf [bkref_str_off++] != buf[sl_str - 1])
-		break; /* We don't need to search this sub expression
-			  any more.  */
-	    }
-	  if (mctx->state_log[sl_str] == NULL)
-	    continue;
-	  /* Does this state have a ')' of the sub expression?  */
-	  nodes = &mctx->state_log[sl_str]->nodes;
-	  cls_node = find_subexp_node (dfa, nodes, subexp_num,
-				       OP_CLOSE_SUBEXP);
-	  if (cls_node == REG_MISSING)
-	    continue; /* No.  */
-	  if (sub_top->path == NULL)
-	    {
-	      sub_top->path = calloc (sizeof (state_array_t),
-				      sl_str - sub_top->str_idx + 1);
-	      if (sub_top->path == NULL)
-		return REG_ESPACE;
-	    }
-	  /* Can the OP_OPEN_SUBEXP node arrive the OP_CLOSE_SUBEXP node
-	     in the current context?  */
-	  err = check_arrival (mctx, sub_top->path, sub_top->node,
-			       sub_top->str_idx, cls_node, sl_str,
-			       OP_CLOSE_SUBEXP);
-	  if (err == REG_NOMATCH)
-	      continue;
-	  if (BE (err != REG_NOERROR, 0))
-	      return err;
-	  sub_last = match_ctx_add_sublast (sub_top, cls_node, sl_str);
-	  if (BE (sub_last == NULL, 0))
-	    return REG_ESPACE;
-	  err = get_subexp_sub (mctx, sub_top, sub_last, bkref_node,
-				bkref_str_idx);
-	  if (err == REG_NOMATCH)
-	    continue;
-	}
-    }
-  return REG_NOERROR;
-}
-
-/* Helper functions for get_subexp().  */
-
-/* Check SUB_LAST can arrive to the back reference BKREF_NODE at BKREF_STR.
-   If it can arrive, register the sub expression expressed with SUB_TOP
-   and SUB_LAST.  */
-
-static reg_errcode_t
-internal_function
-get_subexp_sub (re_match_context_t *mctx, const re_sub_match_top_t *sub_top,
-		re_sub_match_last_t *sub_last, Idx bkref_node, Idx bkref_str)
-{
-  reg_errcode_t err;
-  Idx to_idx;
-  /* Can the subexpression arrive the back reference?  */
-  err = check_arrival (mctx, &sub_last->path, sub_last->node,
-		       sub_last->str_idx, bkref_node, bkref_str,
-		       OP_OPEN_SUBEXP);
-  if (err != REG_NOERROR)
-    return err;
-  err = match_ctx_add_entry (mctx, bkref_node, bkref_str, sub_top->str_idx,
-			     sub_last->str_idx);
-  if (BE (err != REG_NOERROR, 0))
-    return err;
-  to_idx = bkref_str + sub_last->str_idx - sub_top->str_idx;
-  return clean_state_log_if_needed (mctx, to_idx);
-}
-
-/* Find the first node which is '(' or ')' and whose index is SUBEXP_IDX.
-   Search '(' if FL_OPEN, or search ')' otherwise.
-   TODO: This function isn't efficient...
-	 Because there might be more than one nodes whose types are
-	 OP_OPEN_SUBEXP and whose index is SUBEXP_IDX, we must check all
-	 nodes.
-	 E.g. RE: (a){2}  */
-
-static Idx
-internal_function
-find_subexp_node (const re_dfa_t *dfa, const re_node_set *nodes,
-		  Idx subexp_idx, int type)
-{
-  Idx cls_idx;
-  for (cls_idx = 0; cls_idx < nodes->nelem; ++cls_idx)
-    {
-      Idx cls_node = nodes->elems[cls_idx];
-      const re_token_t *node = dfa->nodes + cls_node;
-      if (node->type == type
-	  && node->opr.idx == subexp_idx)
-	return cls_node;
-    }
-  return REG_MISSING;
-}
-
-/* Check whether the node TOP_NODE at TOP_STR can arrive to the node
-   LAST_NODE at LAST_STR.  We record the path onto PATH since it will be
-   heavily reused.
-   Return REG_NOERROR if it can arrive, or REG_NOMATCH otherwise.  */
-
-static reg_errcode_t
-internal_function
-check_arrival (re_match_context_t *mctx, state_array_t *path, Idx top_node,
-	       Idx top_str, Idx last_node, Idx last_str, int type)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  reg_errcode_t err = REG_NOERROR;
-  Idx subexp_num, backup_cur_idx, str_idx, null_cnt;
-  re_dfastate_t *cur_state = NULL;
-  re_node_set *cur_nodes, next_nodes;
-  re_dfastate_t **backup_state_log;
-  unsigned int context;
-
-  subexp_num = dfa->nodes[top_node].opr.idx;
-  /* Extend the buffer if we need.  */
-  if (BE (path->alloc < last_str + mctx->max_mb_elem_len + 1, 0))
-    {
-      re_dfastate_t **new_array;
-      Idx old_alloc = path->alloc;
-      Idx new_alloc = old_alloc + last_str + mctx->max_mb_elem_len + 1;
-      if (BE (new_alloc < old_alloc, 0)
-	  || BE (SIZE_MAX / sizeof (re_dfastate_t *) < new_alloc, 0))
-	return REG_ESPACE;
-      new_array = re_realloc (path->array, re_dfastate_t *, new_alloc);
-      if (BE (new_array == NULL, 0))
-	return REG_ESPACE;
-      path->array = new_array;
-      path->alloc = new_alloc;
-      memset (new_array + old_alloc, '\0',
-	      sizeof (re_dfastate_t *) * (path->alloc - old_alloc));
-    }
-
-  str_idx = path->next_idx ? path->next_idx : top_str;
-
-  /* Temporary modify MCTX.  */
-  backup_state_log = mctx->state_log;
-  backup_cur_idx = mctx->input.cur_idx;
-  mctx->state_log = path->array;
-  mctx->input.cur_idx = str_idx;
-
-  /* Setup initial node set.  */
-  context = re_string_context_at (&mctx->input, str_idx - 1, mctx->eflags);
-  if (str_idx == top_str)
-    {
-      err = re_node_set_init_1 (&next_nodes, top_node);
-      if (BE (err != REG_NOERROR, 0))
-	return err;
-      err = check_arrival_expand_ecl (dfa, &next_nodes, subexp_num, type);
-      if (BE (err != REG_NOERROR, 0))
-	{
-	  re_node_set_free (&next_nodes);
-	  return err;
-	}
-    }
-  else
-    {
-      cur_state = mctx->state_log[str_idx];
-      if (cur_state && cur_state->has_backref)
-	{
-	  err = re_node_set_init_copy (&next_nodes, &cur_state->nodes);
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-	}
-      else
-	re_node_set_init_empty (&next_nodes);
-    }
-  if (str_idx == top_str || (cur_state && cur_state->has_backref))
-    {
-      if (next_nodes.nelem)
-	{
-	  err = expand_bkref_cache (mctx, &next_nodes, str_idx,
-				    subexp_num, type);
-	  if (BE (err != REG_NOERROR, 0))
-	    {
-	      re_node_set_free (&next_nodes);
-	      return err;
-	    }
-	}
-      cur_state = re_acquire_state_context (&err, dfa, &next_nodes, context);
-      if (BE (cur_state == NULL && err != REG_NOERROR, 0))
-	{
-	  re_node_set_free (&next_nodes);
-	  return err;
-	}
-      mctx->state_log[str_idx] = cur_state;
-    }
-
-  for (null_cnt = 0; str_idx < last_str && null_cnt <= mctx->max_mb_elem_len;)
-    {
-      re_node_set_empty (&next_nodes);
-      if (mctx->state_log[str_idx + 1])
-	{
-	  err = re_node_set_merge (&next_nodes,
-				   &mctx->state_log[str_idx + 1]->nodes);
-	  if (BE (err != REG_NOERROR, 0))
-	    {
-	      re_node_set_free (&next_nodes);
-	      return err;
-	    }
-	}
-      if (cur_state)
-	{
-	  err = check_arrival_add_next_nodes (mctx, str_idx,
-					      &cur_state->non_eps_nodes,
-					      &next_nodes);
-	  if (BE (err != REG_NOERROR, 0))
-	    {
-	      re_node_set_free (&next_nodes);
-	      return err;
-	    }
-	}
-      ++str_idx;
-      if (next_nodes.nelem)
-	{
-	  err = check_arrival_expand_ecl (dfa, &next_nodes, subexp_num, type);
-	  if (BE (err != REG_NOERROR, 0))
-	    {
-	      re_node_set_free (&next_nodes);
-	      return err;
-	    }
-	  err = expand_bkref_cache (mctx, &next_nodes, str_idx,
-				    subexp_num, type);
-	  if (BE (err != REG_NOERROR, 0))
-	    {
-	      re_node_set_free (&next_nodes);
-	      return err;
-	    }
-	}
-      context = re_string_context_at (&mctx->input, str_idx - 1, mctx->eflags);
-      cur_state = re_acquire_state_context (&err, dfa, &next_nodes, context);
-      if (BE (cur_state == NULL && err != REG_NOERROR, 0))
-	{
-	  re_node_set_free (&next_nodes);
-	  return err;
-	}
-      mctx->state_log[str_idx] = cur_state;
-      null_cnt = cur_state == NULL ? null_cnt + 1 : 0;
-    }
-  re_node_set_free (&next_nodes);
-  cur_nodes = (mctx->state_log[last_str] == NULL ? NULL
-	       : &mctx->state_log[last_str]->nodes);
-  path->next_idx = str_idx;
-
-  /* Fix MCTX.  */
-  mctx->state_log = backup_state_log;
-  mctx->input.cur_idx = backup_cur_idx;
-
-  /* Then check the current node set has the node LAST_NODE.  */
-  if (cur_nodes != NULL && re_node_set_contains (cur_nodes, last_node))
-    return REG_NOERROR;
-
-  return REG_NOMATCH;
-}
-
-/* Helper functions for check_arrival.  */
-
-/* Calculate the destination nodes of CUR_NODES at STR_IDX, and append them
-   to NEXT_NODES.
-   TODO: This function is similar to the functions transit_state*(),
-	 however this function has many additional works.
-	 Can't we unify them?  */
-
-static reg_errcode_t
-internal_function
-check_arrival_add_next_nodes (re_match_context_t *mctx, Idx str_idx,
-			      re_node_set *cur_nodes, re_node_set *next_nodes)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  bool ok;
-  Idx cur_idx;
-  reg_errcode_t err = REG_NOERROR;
-  re_node_set union_set;
-  re_node_set_init_empty (&union_set);
-  for (cur_idx = 0; cur_idx < cur_nodes->nelem; ++cur_idx)
-    {
-      int naccepted = 0;
-      Idx cur_node = cur_nodes->elems[cur_idx];
-#ifdef DEBUG
-      re_token_type_t type = dfa->nodes[cur_node].type;
-      assert (!IS_EPSILON_NODE (type));
-#endif
-#ifdef RE_ENABLE_I18N
-      /* If the node may accept `multi byte'.  */
-      if (dfa->nodes[cur_node].accept_mb)
-	{
-	  naccepted = check_node_accept_bytes (dfa, cur_node, &mctx->input,
-					       str_idx);
-	  if (naccepted > 1)
-	    {
-	      re_dfastate_t *dest_state;
-	      Idx next_node = dfa->nexts[cur_node];
-	      Idx next_idx = str_idx + naccepted;
-	      dest_state = mctx->state_log[next_idx];
-	      re_node_set_empty (&union_set);
-	      if (dest_state)
-		{
-		  err = re_node_set_merge (&union_set, &dest_state->nodes);
-		  if (BE (err != REG_NOERROR, 0))
-		    {
-		      re_node_set_free (&union_set);
-		      return err;
-		    }
-		}
-	      ok = re_node_set_insert (&union_set, next_node);
-	      if (BE (! ok, 0))
-		{
-		  re_node_set_free (&union_set);
-		  return REG_ESPACE;
-		}
-	      mctx->state_log[next_idx] = re_acquire_state (&err, dfa,
-							    &union_set);
-	      if (BE (mctx->state_log[next_idx] == NULL
-		      && err != REG_NOERROR, 0))
-		{
-		  re_node_set_free (&union_set);
-		  return err;
-		}
-	    }
-	}
-#endif /* RE_ENABLE_I18N */
-      if (naccepted
-	  || check_node_accept (mctx, dfa->nodes + cur_node, str_idx))
-	{
-	  ok = re_node_set_insert (next_nodes, dfa->nexts[cur_node]);
-	  if (BE (! ok, 0))
-	    {
-	      re_node_set_free (&union_set);
-	      return REG_ESPACE;
-	    }
-	}
-    }
-  re_node_set_free (&union_set);
-  return REG_NOERROR;
-}
-
-/* For all the nodes in CUR_NODES, add the epsilon closures of them to
-   CUR_NODES, however exclude the nodes which are:
-    - inside the sub expression whose number is EX_SUBEXP, if FL_OPEN.
-    - out of the sub expression whose number is EX_SUBEXP, if !FL_OPEN.
-*/
-
-static reg_errcode_t
-internal_function
-check_arrival_expand_ecl (const re_dfa_t *dfa, re_node_set *cur_nodes,
-			  Idx ex_subexp, int type)
-{
-  reg_errcode_t err;
-  Idx idx, outside_node;
-  re_node_set new_nodes;
-#ifdef DEBUG
-  assert (cur_nodes->nelem);
-#endif
-  err = re_node_set_alloc (&new_nodes, cur_nodes->nelem);
-  if (BE (err != REG_NOERROR, 0))
-    return err;
-  /* Create a new node set NEW_NODES with the nodes which are epsilon
-     closures of the node in CUR_NODES.  */
-
-  for (idx = 0; idx < cur_nodes->nelem; ++idx)
-    {
-      Idx cur_node = cur_nodes->elems[idx];
-      const re_node_set *eclosure = dfa->eclosures + cur_node;
-      outside_node = find_subexp_node (dfa, eclosure, ex_subexp, type);
-      if (outside_node == REG_MISSING)
-	{
-	  /* There are no problematic nodes, just merge them.  */
-	  err = re_node_set_merge (&new_nodes, eclosure);
-	  if (BE (err != REG_NOERROR, 0))
-	    {
-	      re_node_set_free (&new_nodes);
-	      return err;
-	    }
-	}
-      else
-	{
-	  /* There are problematic nodes, re-calculate incrementally.  */
-	  err = check_arrival_expand_ecl_sub (dfa, &new_nodes, cur_node,
-					      ex_subexp, type);
-	  if (BE (err != REG_NOERROR, 0))
-	    {
-	      re_node_set_free (&new_nodes);
-	      return err;
-	    }
-	}
-    }
-  re_node_set_free (cur_nodes);
-  *cur_nodes = new_nodes;
-  return REG_NOERROR;
-}
-
-/* Helper function for check_arrival_expand_ecl.
-   Check incrementally the epsilon closure of TARGET, and if it isn't
-   problematic append it to DST_NODES.  */
-
-static reg_errcode_t
-internal_function
-check_arrival_expand_ecl_sub (const re_dfa_t *dfa, re_node_set *dst_nodes,
-			      Idx target, Idx ex_subexp, int type)
-{
-  Idx cur_node;
-  for (cur_node = target; !re_node_set_contains (dst_nodes, cur_node);)
-    {
-      bool ok;
-
-      if (dfa->nodes[cur_node].type == type
-	  && dfa->nodes[cur_node].opr.idx == ex_subexp)
-	{
-	  if (type == OP_CLOSE_SUBEXP)
-	    {
-	      ok = re_node_set_insert (dst_nodes, cur_node);
-	      if (BE (! ok, 0))
-		return REG_ESPACE;
-	    }
-	  break;
-	}
-      ok = re_node_set_insert (dst_nodes, cur_node);
-      if (BE (! ok, 0))
-	return REG_ESPACE;
-      if (dfa->edests[cur_node].nelem == 0)
-	break;
-      if (dfa->edests[cur_node].nelem == 2)
-	{
-	  reg_errcode_t err;
-	  err = check_arrival_expand_ecl_sub (dfa, dst_nodes,
-					      dfa->edests[cur_node].elems[1],
-					      ex_subexp, type);
-	  if (BE (err != REG_NOERROR, 0))
-	    return err;
-	}
-      cur_node = dfa->edests[cur_node].elems[0];
-    }
-  return REG_NOERROR;
-}
-
-
-/* For all the back references in the current state, calculate the
-   destination of the back references by the appropriate entry
-   in MCTX->BKREF_ENTS.  */
-
-static reg_errcode_t
-internal_function
-expand_bkref_cache (re_match_context_t *mctx, re_node_set *cur_nodes,
-		    Idx cur_str, Idx subexp_num, int type)
-{
-  const re_dfa_t *const dfa = mctx->dfa;
-  reg_errcode_t err;
-  Idx cache_idx_start = search_cur_bkref_entry (mctx, cur_str);
-  struct re_backref_cache_entry *ent;
-
-  if (cache_idx_start == REG_MISSING)
-    return REG_NOERROR;
-
- restart:
-  ent = mctx->bkref_ents + cache_idx_start;
-  do
-    {
-      Idx to_idx, next_node;
-
-      /* Is this entry ENT is appropriate?  */
-      if (!re_node_set_contains (cur_nodes, ent->node))
-	continue; /* No.  */
-
-      to_idx = cur_str + ent->subexp_to - ent->subexp_from;
-      /* Calculate the destination of the back reference, and append it
-	 to MCTX->STATE_LOG.  */
-      if (to_idx == cur_str)
-	{
-	  /* The backreference did epsilon transit, we must re-check all the
-	     node in the current state.  */
-	  re_node_set new_dests;
-	  reg_errcode_t err2, err3;
-	  next_node = dfa->edests[ent->node].elems[0];
-	  if (re_node_set_contains (cur_nodes, next_node))
-	    continue;
-	  err = re_node_set_init_1 (&new_dests, next_node);
-	  err2 = check_arrival_expand_ecl (dfa, &new_dests, subexp_num, type);
-	  err3 = re_node_set_merge (cur_nodes, &new_dests);
-	  re_node_set_free (&new_dests);
-	  if (BE (err != REG_NOERROR || err2 != REG_NOERROR
-		  || err3 != REG_NOERROR, 0))
-	    {
-	      err = (err != REG_NOERROR ? err
-		     : (err2 != REG_NOERROR ? err2 : err3));
-	      return err;
-	    }
-	  /* TODO: It is still inefficient...  */
-	  goto restart;
-	}
-      else
-	{
-	  re_node_set union_set;
-	  next_node = dfa->nexts[ent->node];
-	  if (mctx->state_log[to_idx])
-	    {
-	      bool ok;
-	      if (re_node_set_contains (&mctx->state_log[to_idx]->nodes,
-					next_node))
-		continue;
-	      err = re_node_set_init_copy (&union_set,
-					   &mctx->state_log[to_idx]->nodes);
-	      ok = re_node_set_insert (&union_set, next_node);
-	      if (BE (err != REG_NOERROR || ! ok, 0))
-		{
-		  re_node_set_free (&union_set);
-		  err = err != REG_NOERROR ? err : REG_ESPACE;
-		  return err;
-		}
-	    }
-	  else
-	    {
-	      err = re_node_set_init_1 (&union_set, next_node);
-	      if (BE (err != REG_NOERROR, 0))
-		return err;
-	    }
-	  mctx->state_log[to_idx] = re_acquire_state (&err, dfa, &union_set);
-	  re_node_set_free (&union_set);
-	  if (BE (mctx->state_log[to_idx] == NULL
-		  && err != REG_NOERROR, 0))
-	    return err;
-	}
-    }
-  while (ent++->more);
-  return REG_NOERROR;
-}
-
-/* Build transition table for the state.
-   Return true if successful.  */
-
-static bool
-internal_function
-build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
-{
-  reg_errcode_t err;
-  Idx i, j;
-  int ch;
-  bool need_word_trtable = false;
-  bitset_word_t elem, mask;
-  bool dests_node_malloced = false;
-  bool dest_states_malloced = false;
-  Idx ndests; /* Number of the destination states from `state'.  */
-  re_dfastate_t **trtable;
-  re_dfastate_t **dest_states = NULL, **dest_states_word, **dest_states_nl;
-  re_node_set follows, *dests_node;
-  bitset_t *dests_ch;
-  bitset_t acceptable;
-
-  struct dests_alloc
-  {
-    re_node_set dests_node[SBC_MAX];
-    bitset_t dests_ch[SBC_MAX];
-  } *dests_alloc;
-
-  /* We build DFA states which corresponds to the destination nodes
-     from `state'.  `dests_node[i]' represents the nodes which i-th
-     destination state contains, and `dests_ch[i]' represents the
-     characters which i-th destination state accepts.  */
-  if (__libc_use_alloca (sizeof (struct dests_alloc)))
-    dests_alloc = (struct dests_alloc *) alloca (sizeof (struct dests_alloc));
-  else
-    {
-      dests_alloc = re_malloc (struct dests_alloc, 1);
-      if (BE (dests_alloc == NULL, 0))
-	return false;
-      dests_node_malloced = true;
-    }
-  dests_node = dests_alloc->dests_node;
-  dests_ch = dests_alloc->dests_ch;
-
-  /* Initialize transiton table.  */
-  state->word_trtable = state->trtable = NULL;
-
-  /* At first, group all nodes belonging to `state' into several
-     destinations.  */
-  ndests = group_nodes_into_DFAstates (dfa, state, dests_node, dests_ch);
-  if (BE (! REG_VALID_NONZERO_INDEX (ndests), 0))
-    {
-      if (dests_node_malloced)
-	free (dests_alloc);
-      if (ndests == 0)
-	{
-	  state->trtable = (re_dfastate_t **)
-	    calloc (sizeof (re_dfastate_t *), SBC_MAX);
-	  return true;
-	}
-      return false;
-    }
-
-  err = re_node_set_alloc (&follows, ndests + 1);
-  if (BE (err != REG_NOERROR, 0))
-    goto out_free;
-
-  /* Avoid arithmetic overflow in size calculation.  */
-  if (BE ((((SIZE_MAX - (sizeof (re_node_set) + sizeof (bitset_t)) * SBC_MAX)
-	    / (3 * sizeof (re_dfastate_t *)))
-	   < ndests),
-	  0))
-    goto out_free;
-
-  if (__libc_use_alloca ((sizeof (re_node_set) + sizeof (bitset_t)) * SBC_MAX
-			 + ndests * 3 * sizeof (re_dfastate_t *)))
-    dest_states = (re_dfastate_t **)
-      alloca (ndests * 3 * sizeof (re_dfastate_t *));
-  else
-    {
-      dest_states = (re_dfastate_t **)
-	malloc (ndests * 3 * sizeof (re_dfastate_t *));
-      if (BE (dest_states == NULL, 0))
-	{
-out_free:
-	  if (dest_states_malloced)
-	    free (dest_states);
-	  re_node_set_free (&follows);
-	  for (i = 0; i < ndests; ++i)
-	    re_node_set_free (dests_node + i);
-	  if (dests_node_malloced)
-	    free (dests_alloc);
-	  return false;
-	}
-      dest_states_malloced = true;
-    }
-  dest_states_word = dest_states + ndests;
-  dest_states_nl = dest_states_word + ndests;
-  bitset_empty (acceptable);
-
-  /* Then build the states for all destinations.  */
-  for (i = 0; i < ndests; ++i)
-    {
-      Idx next_node;
-      re_node_set_empty (&follows);
-      /* Merge the follows of this destination states.  */
-      for (j = 0; j < dests_node[i].nelem; ++j)
-	{
-	  next_node = dfa->nexts[dests_node[i].elems[j]];
-	  if (next_node != REG_MISSING)
-	    {
-	      err = re_node_set_merge (&follows, dfa->eclosures + next_node);
-	      if (BE (err != REG_NOERROR, 0))
-		goto out_free;
-	    }
-	}
-      dest_states[i] = re_acquire_state_context (&err, dfa, &follows, 0);
-      if (BE (dest_states[i] == NULL && err != REG_NOERROR, 0))
-	goto out_free;
-      /* If the new state has context constraint,
-	 build appropriate states for these contexts.  */
-      if (dest_states[i]->has_constraint)
-	{
-	  dest_states_word[i] = re_acquire_state_context (&err, dfa, &follows,
-							  CONTEXT_WORD);
-	  if (BE (dest_states_word[i] == NULL && err != REG_NOERROR, 0))
-	    goto out_free;
-
-	  if (dest_states[i] != dest_states_word[i] && dfa->mb_cur_max > 1)
-	    need_word_trtable = true;
-
-	  dest_states_nl[i] = re_acquire_state_context (&err, dfa, &follows,
-							CONTEXT_NEWLINE);
-	  if (BE (dest_states_nl[i] == NULL && err != REG_NOERROR, 0))
-	    goto out_free;
- 	}
-      else
-	{
-	  dest_states_word[i] = dest_states[i];
-	  dest_states_nl[i] = dest_states[i];
-	}
-      bitset_merge (acceptable, dests_ch[i]);
-    }
-
-  if (!BE (need_word_trtable, 0))
-    {
-      /* We don't care about whether the following character is a word
-	 character, or we are in a single-byte character set so we can
-	 discern by looking at the character code: allocate a
-	 256-entry transition table.  */
-      trtable = state->trtable =
-	(re_dfastate_t **) calloc (sizeof (re_dfastate_t *), SBC_MAX);
-      if (BE (trtable == NULL, 0))
-	goto out_free;
-
-      /* For all characters ch...:  */
-      for (i = 0; i < BITSET_WORDS; ++i)
-	for (ch = i * BITSET_WORD_BITS, elem = acceptable[i], mask = 1;
-	     elem;
-	     mask <<= 1, elem >>= 1, ++ch)
-	  if (BE (elem & 1, 0))
-	    {
-	      /* There must be exactly one destination which accepts
-		 character ch.  See group_nodes_into_DFAstates.  */
-	      for (j = 0; (dests_ch[j][i] & mask) == 0; ++j)
-		;
-
-	      /* j-th destination accepts the word character ch.  */
-	      if (dfa->word_char[i] & mask)
-		trtable[ch] = dest_states_word[j];
-	      else
-		trtable[ch] = dest_states[j];
-	    }
-    }
-  else
-    {
-      /* We care about whether the following character is a word
-	 character, and we are in a multi-byte character set: discern
-	 by looking at the character code: build two 256-entry
-	 transition tables, one starting at trtable[0] and one
-	 starting at trtable[SBC_MAX].  */
-      trtable = state->word_trtable =
-	(re_dfastate_t **) calloc (sizeof (re_dfastate_t *), 2 * SBC_MAX);
-      if (BE (trtable == NULL, 0))
-	goto out_free;
-
-      /* For all characters ch...:  */
-      for (i = 0; i < BITSET_WORDS; ++i)
-	for (ch = i * BITSET_WORD_BITS, elem = acceptable[i], mask = 1;
-	     elem;
-	     mask <<= 1, elem >>= 1, ++ch)
-	  if (BE (elem & 1, 0))
-	    {
-	      /* There must be exactly one destination which accepts
-		 character ch.  See group_nodes_into_DFAstates.  */
-	      for (j = 0; (dests_ch[j][i] & mask) == 0; ++j)
-		;
-
-	      /* j-th destination accepts the word character ch.  */
-	      trtable[ch] = dest_states[j];
-	      trtable[ch + SBC_MAX] = dest_states_word[j];
-	    }
-    }
-
-  /* new line */
-  if (bitset_contain (acceptable, NEWLINE_CHAR))
-    {
-      /* The current state accepts newline character.  */
-      for (j = 0; j < ndests; ++j)
-	if (bitset_contain (dests_ch[j], NEWLINE_CHAR))
-	  {
-	    /* k-th destination accepts newline character.  */
-	    trtable[NEWLINE_CHAR] = dest_states_nl[j];
-	    if (need_word_trtable)
-	      trtable[NEWLINE_CHAR + SBC_MAX] = dest_states_nl[j];
-	    /* There must be only one destination which accepts
-	       newline.  See group_nodes_into_DFAstates.  */
-	    break;
-	  }
-    }
-
-  if (dest_states_malloced)
-    free (dest_states);
-
-  re_node_set_free (&follows);
-  for (i = 0; i < ndests; ++i)
-    re_node_set_free (dests_node + i);
-
-  if (dests_node_malloced)
-    free (dests_alloc);
-
-  return true;
-}
-
-/* Group all nodes belonging to STATE into several destinations.
-   Then for all destinations, set the nodes belonging to the destination
-   to DESTS_NODE[i] and set the characters accepted by the destination
-   to DEST_CH[i].  This function return the number of destinations.  */
-
-static Idx
-internal_function
-group_nodes_into_DFAstates (const re_dfa_t *dfa, const re_dfastate_t *state,
-			    re_node_set *dests_node, bitset_t *dests_ch)
-{
-  reg_errcode_t err;
-  bool ok;
-  Idx i, j, k;
-  Idx ndests; /* Number of the destinations from `state'.  */
-  bitset_t accepts; /* Characters a node can accept.  */
-  const re_node_set *cur_nodes = &state->nodes;
-  bitset_empty (accepts);
-  ndests = 0;
-
-  /* For all the nodes belonging to `state',  */
-  for (i = 0; i < cur_nodes->nelem; ++i)
-    {
-      re_token_t *node = &dfa->nodes[cur_nodes->elems[i]];
-      re_token_type_t type = node->type;
-      unsigned int constraint = node->constraint;
-
-      /* Enumerate all single byte character this node can accept.  */
-      if (type == CHARACTER)
-	bitset_set (accepts, node->opr.c);
-      else if (type == SIMPLE_BRACKET)
-	{
-	  bitset_merge (accepts, node->opr.sbcset);
-	}
-      else if (type == OP_PERIOD)
-	{
-#ifdef RE_ENABLE_I18N
-	  if (dfa->mb_cur_max > 1)
-	    bitset_merge (accepts, dfa->sb_char);
-	  else
-#endif
-	    bitset_set_all (accepts);
-	  if (!(dfa->syntax & RE_DOT_NEWLINE))
-	    bitset_clear (accepts, '\n');
-	  if (dfa->syntax & RE_DOT_NOT_NULL)
-	    bitset_clear (accepts, '\0');
-	}
-#ifdef RE_ENABLE_I18N
-      else if (type == OP_UTF8_PERIOD)
-        {
-	  if (ASCII_CHARS % BITSET_WORD_BITS == 0)
-	    memset (accepts, -1, ASCII_CHARS / CHAR_BIT);
-	  else
-	    bitset_merge (accepts, utf8_sb_map);
-	  if (!(dfa->syntax & RE_DOT_NEWLINE))
-	    bitset_clear (accepts, '\n');
-	  if (dfa->syntax & RE_DOT_NOT_NULL)
-	    bitset_clear (accepts, '\0');
-        }
-#endif
-      else
-	continue;
-
-      /* Check the `accepts' and sift the characters which are not
-	 match it the context.  */
-      if (constraint)
-	{
-	  if (constraint & NEXT_NEWLINE_CONSTRAINT)
-	    {
-	      bool accepts_newline = bitset_contain (accepts, NEWLINE_CHAR);
-	      bitset_empty (accepts);
-	      if (accepts_newline)
-		bitset_set (accepts, NEWLINE_CHAR);
-	      else
-		continue;
-	    }
-	  if (constraint & NEXT_ENDBUF_CONSTRAINT)
-	    {
-	      bitset_empty (accepts);
-	      continue;
-	    }
-
-	  if (constraint & NEXT_WORD_CONSTRAINT)
-	    {
-	      bitset_word_t any_set = 0;
-	      if (type == CHARACTER && !node->word_char)
-		{
-		  bitset_empty (accepts);
-		  continue;
-		}
-#ifdef RE_ENABLE_I18N
-	      if (dfa->mb_cur_max > 1)
-		for (j = 0; j < BITSET_WORDS; ++j)
-		  any_set |= (accepts[j] &= (dfa->word_char[j] | ~dfa->sb_char[j]));
-	      else
-#endif
-		for (j = 0; j < BITSET_WORDS; ++j)
-		  any_set |= (accepts[j] &= dfa->word_char[j]);
-	      if (!any_set)
-		continue;
-	    }
-	  if (constraint & NEXT_NOTWORD_CONSTRAINT)
-	    {
-	      bitset_word_t any_set = 0;
-	      if (type == CHARACTER && node->word_char)
-		{
-		  bitset_empty (accepts);
-		  continue;
-		}
-#ifdef RE_ENABLE_I18N
-	      if (dfa->mb_cur_max > 1)
-		for (j = 0; j < BITSET_WORDS; ++j)
-		  any_set |= (accepts[j] &= ~(dfa->word_char[j] & dfa->sb_char[j]));
-	      else
-#endif
-		for (j = 0; j < BITSET_WORDS; ++j)
-		  any_set |= (accepts[j] &= ~dfa->word_char[j]);
-	      if (!any_set)
-		continue;
-	    }
-	}
-
-      /* Then divide `accepts' into DFA states, or create a new
-	 state.  Above, we make sure that accepts is not empty.  */
-      for (j = 0; j < ndests; ++j)
-	{
-	  bitset_t intersec; /* Intersection sets, see below.  */
-	  bitset_t remains;
-	  /* Flags, see below.  */
-	  bitset_word_t has_intersec, not_subset, not_consumed;
-
-	  /* Optimization, skip if this state doesn't accept the character.  */
-	  if (type == CHARACTER && !bitset_contain (dests_ch[j], node->opr.c))
-	    continue;
-
-	  /* Enumerate the intersection set of this state and `accepts'.  */
-	  has_intersec = 0;
-	  for (k = 0; k < BITSET_WORDS; ++k)
-	    has_intersec |= intersec[k] = accepts[k] & dests_ch[j][k];
-	  /* And skip if the intersection set is empty.  */
-	  if (!has_intersec)
-	    continue;
-
-	  /* Then check if this state is a subset of `accepts'.  */
-	  not_subset = not_consumed = 0;
-	  for (k = 0; k < BITSET_WORDS; ++k)
-	    {
-	      not_subset |= remains[k] = ~accepts[k] & dests_ch[j][k];
-	      not_consumed |= accepts[k] = accepts[k] & ~dests_ch[j][k];
-	    }
-
-	  /* If this state isn't a subset of `accepts', create a
-	     new group state, which has the `remains'. */
-	  if (not_subset)
-	    {
-	      bitset_copy (dests_ch[ndests], remains);
-	      bitset_copy (dests_ch[j], intersec);
-	      err = re_node_set_init_copy (dests_node + ndests, &dests_node[j]);
-	      if (BE (err != REG_NOERROR, 0))
-		goto error_return;
-	      ++ndests;
-	    }
-
-	  /* Put the position in the current group. */
-	  ok = re_node_set_insert (&dests_node[j], cur_nodes->elems[i]);
-	  if (BE (! ok, 0))
-	    goto error_return;
-
-	  /* If all characters are consumed, go to next node. */
-	  if (!not_consumed)
-	    break;
-	}
-      /* Some characters remain, create a new group. */
-      if (j == ndests)
-	{
-	  bitset_copy (dests_ch[ndests], accepts);
-	  err = re_node_set_init_1 (dests_node + ndests, cur_nodes->elems[i]);
-	  if (BE (err != REG_NOERROR, 0))
-	    goto error_return;
-	  ++ndests;
-	  bitset_empty (accepts);
-	}
-    }
-  return ndests;
- error_return:
-  for (j = 0; j < ndests; ++j)
-    re_node_set_free (dests_node + j);
-  return REG_MISSING;
-}
-
-#ifdef RE_ENABLE_I18N
-/* Check how many bytes the node `dfa->nodes[node_idx]' accepts.
-   Return the number of the bytes the node accepts.
-   STR_IDX is the current index of the input string.
-
-   This function handles the nodes which can accept one character, or
-   one collating element like '.', '[a-z]', opposite to the other nodes
-   can only accept one byte.  */
-
-static int
-internal_function
-check_node_accept_bytes (const re_dfa_t *dfa, Idx node_idx,
-			 const re_string_t *input, Idx str_idx)
-{
-  const re_token_t *node = dfa->nodes + node_idx;
-  int char_len, elem_len;
-  Idx i;
-
-  if (BE (node->type == OP_UTF8_PERIOD, 0))
-    {
-      unsigned char c = re_string_byte_at (input, str_idx), d;
-      if (BE (c < 0xc2, 1))
-	return 0;
-
-      if (str_idx + 2 > input->len)
-	return 0;
-
-      d = re_string_byte_at (input, str_idx + 1);
-      if (c < 0xe0)
-	return (d < 0x80 || d > 0xbf) ? 0 : 2;
-      else if (c < 0xf0)
-	{
-	  char_len = 3;
-	  if (c == 0xe0 && d < 0xa0)
-	    return 0;
-	}
-      else if (c < 0xf8)
-	{
-	  char_len = 4;
-	  if (c == 0xf0 && d < 0x90)
-	    return 0;
-	}
-      else if (c < 0xfc)
-	{
-	  char_len = 5;
-	  if (c == 0xf8 && d < 0x88)
-	    return 0;
-	}
-      else if (c < 0xfe)
-	{
-	  char_len = 6;
-	  if (c == 0xfc && d < 0x84)
-	    return 0;
-	}
-      else
-	return 0;
-
-      if (str_idx + char_len > input->len)
-	return 0;
-
-      for (i = 1; i < char_len; ++i)
-	{
-	  d = re_string_byte_at (input, str_idx + i);
-	  if (d < 0x80 || d > 0xbf)
-	    return 0;
-	}
-      return char_len;
-    }
-
-  char_len = re_string_char_size_at (input, str_idx);
-  if (node->type == OP_PERIOD)
-    {
-      if (char_len <= 1)
-        return 0;
-      /* FIXME: I don't think this if is needed, as both '\n'
-	 and '\0' are char_len == 1.  */
-      /* '.' accepts any one character except the following two cases.  */
-      if ((!(dfa->syntax & RE_DOT_NEWLINE) &&
-	   re_string_byte_at (input, str_idx) == '\n') ||
-	  ((dfa->syntax & RE_DOT_NOT_NULL) &&
-	   re_string_byte_at (input, str_idx) == '\0'))
-	return 0;
-      return char_len;
-    }
-
-  elem_len = re_string_elem_size_at (input, str_idx);
-  if ((elem_len <= 1 && char_len <= 1) || char_len == 0)
-    return 0;
-
-  if (node->type == COMPLEX_BRACKET)
-    {
-      const re_charset_t *cset = node->opr.mbcset;
-# ifdef _LIBC
-      const unsigned char *pin
-	= ((const unsigned char *) re_string_get_buffer (input) + str_idx);
-      Idx j;
-      uint32_t nrules;
-# endif /* _LIBC */
-      int match_len = 0;
-      wchar_t wc = ((cset->nranges || cset->nchar_classes || cset->nmbchars)
-		    ? re_string_wchar_at (input, str_idx) : 0);
-
-      /* match with multibyte character?  */
-      for (i = 0; i < cset->nmbchars; ++i)
-	if (wc == cset->mbchars[i])
-	  {
-	    match_len = char_len;
-	    goto check_node_accept_bytes_match;
-	  }
-      /* match with character_class?  */
-      for (i = 0; i < cset->nchar_classes; ++i)
-	{
-	  wctype_t wt = cset->char_classes[i];
-	  if (__iswctype (wc, wt))
-	    {
-	      match_len = char_len;
-	      goto check_node_accept_bytes_match;
-	    }
-	}
-
-# ifdef _LIBC
-      nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
-      if (nrules != 0)
-	{
-	  unsigned int in_collseq = 0;
-	  const int32_t *table, *indirect;
-	  const unsigned char *weights, *extra;
-	  const char *collseqwc;
-	  int32_t idx;
-	  /* This #include defines a local function!  */
-#  include <locale/weight.h>
-
-	  /* match with collating_symbol?  */
-	  if (cset->ncoll_syms)
-	    extra = (const unsigned char *)
-	      _NL_CURRENT (LC_COLLATE, _NL_COLLATE_SYMB_EXTRAMB);
-	  for (i = 0; i < cset->ncoll_syms; ++i)
-	    {
-	      const unsigned char *coll_sym = extra + cset->coll_syms[i];
-	      /* Compare the length of input collating element and
-		 the length of current collating element.  */
-	      if (*coll_sym != elem_len)
-		continue;
-	      /* Compare each bytes.  */
-	      for (j = 0; j < *coll_sym; j++)
-		if (pin[j] != coll_sym[1 + j])
-		  break;
-	      if (j == *coll_sym)
-		{
-		  /* Match if every bytes is equal.  */
-		  match_len = j;
-		  goto check_node_accept_bytes_match;
-		}
-	    }
-
-	  if (cset->nranges)
-	    {
-	      if (elem_len <= char_len)
-		{
-		  collseqwc = _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQWC);
-		  in_collseq = __collseq_table_lookup (collseqwc, wc);
-		}
-	      else
-		in_collseq = find_collation_sequence_value (pin, elem_len);
-	    }
-	  /* match with range expression?  */
-	  for (i = 0; i < cset->nranges; ++i)
-	    if (cset->range_starts[i] <= in_collseq
-		&& in_collseq <= cset->range_ends[i])
-	      {
-		match_len = elem_len;
-		goto check_node_accept_bytes_match;
-	      }
-
-	  /* match with equivalence_class?  */
-	  if (cset->nequiv_classes)
-	    {
-	      const unsigned char *cp = pin;
-	      table = (const int32_t *)
-		_NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
-	      weights = (const unsigned char *)
-		_NL_CURRENT (LC_COLLATE, _NL_COLLATE_WEIGHTMB);
-	      extra = (const unsigned char *)
-		_NL_CURRENT (LC_COLLATE, _NL_COLLATE_EXTRAMB);
-	      indirect = (const int32_t *)
-		_NL_CURRENT (LC_COLLATE, _NL_COLLATE_INDIRECTMB);
-	      idx = findidx (&cp);
-	      if (idx > 0)
-		for (i = 0; i < cset->nequiv_classes; ++i)
-		  {
-		    int32_t equiv_class_idx = cset->equiv_classes[i];
-		    size_t weight_len = weights[idx];
-		    if (weight_len == weights[equiv_class_idx])
-		      {
-			Idx cnt = 0;
-			while (cnt <= weight_len
-			       && (weights[equiv_class_idx + 1 + cnt]
-				   == weights[idx + 1 + cnt]))
-			  ++cnt;
-			if (cnt > weight_len)
-			  {
-			    match_len = elem_len;
-			    goto check_node_accept_bytes_match;
-			  }
-		      }
-		  }
-	    }
-	}
-      else
-# endif /* _LIBC */
-	{
-	  /* match with range expression?  */
-#if __GNUC__ >= 2 && ! (__STDC_VERSION__ < 199901L && __STRICT_ANSI__)
-	  wchar_t cmp_buf[] = {L'\0', L'\0', wc, L'\0', L'\0', L'\0'};
-#else
-	  wchar_t cmp_buf[] = {L'\0', L'\0', L'\0', L'\0', L'\0', L'\0'};
-	  cmp_buf[2] = wc;
-#endif
-	  for (i = 0; i < cset->nranges; ++i)
-	    {
-	      cmp_buf[0] = cset->range_starts[i];
-	      cmp_buf[4] = cset->range_ends[i];
-	      if (wcscoll (cmp_buf, cmp_buf + 2) <= 0
-		  && wcscoll (cmp_buf + 2, cmp_buf + 4) <= 0)
-		{
-		  match_len = char_len;
-		  goto check_node_accept_bytes_match;
-		}
-	    }
-	}
-    check_node_accept_bytes_match:
-      if (!cset->non_match)
-	return match_len;
-      else
-	{
-	  if (match_len > 0)
-	    return 0;
-	  else
-	    return (elem_len > char_len) ? elem_len : char_len;
-	}
-    }
-  return 0;
-}
-
-# ifdef _LIBC
-static unsigned int
-internal_function
-find_collation_sequence_value (const unsigned char *mbs, size_t mbs_len)
-{
-  uint32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
-  if (nrules == 0)
-    {
-      if (mbs_len == 1)
-	{
-	  /* No valid character.  Match it as a single byte character.  */
-	  const unsigned char *collseq = (const unsigned char *)
-	    _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQMB);
-	  return collseq[mbs[0]];
-	}
-      return UINT_MAX;
-    }
-  else
-    {
-      int32_t idx;
-      const unsigned char *extra = (const unsigned char *)
-	_NL_CURRENT (LC_COLLATE, _NL_COLLATE_SYMB_EXTRAMB);
-      int32_t extrasize = (const unsigned char *)
-	_NL_CURRENT (LC_COLLATE, _NL_COLLATE_SYMB_EXTRAMB + 1) - extra;
-
-      for (idx = 0; idx < extrasize;)
-	{
-	  int mbs_cnt;
-	  bool found = false;
-	  int32_t elem_mbs_len;
-	  /* Skip the name of collating element name.  */
-	  idx = idx + extra[idx] + 1;
-	  elem_mbs_len = extra[idx++];
-	  if (mbs_len == elem_mbs_len)
-	    {
-	      for (mbs_cnt = 0; mbs_cnt < elem_mbs_len; ++mbs_cnt)
-		if (extra[idx + mbs_cnt] != mbs[mbs_cnt])
-		  break;
-	      if (mbs_cnt == elem_mbs_len)
-		/* Found the entry.  */
-		found = true;
-	    }
-	  /* Skip the byte sequence of the collating element.  */
-	  idx += elem_mbs_len;
-	  /* Adjust for the alignment.  */
-	  idx = (idx + 3) & ~3;
-	  /* Skip the collation sequence value.  */
-	  idx += sizeof (uint32_t);
-	  /* Skip the wide char sequence of the collating element.  */
-	  idx = idx + sizeof (uint32_t) * (extra[idx] + 1);
-	  /* If we found the entry, return the sequence value.  */
-	  if (found)
-	    return *(uint32_t *) (extra + idx);
-	  /* Skip the collation sequence value.  */
-	  idx += sizeof (uint32_t);
-	}
-      return UINT_MAX;
-    }
-}
-# endif /* _LIBC */
-#endif /* RE_ENABLE_I18N */
-
-/* Check whether the node accepts the byte which is IDX-th
-   byte of the INPUT.  */
-
-static bool
-internal_function
-check_node_accept (const re_match_context_t *mctx, const re_token_t *node,
-		   Idx idx)
-{
-  unsigned char ch;
-  ch = re_string_byte_at (&mctx->input, idx);
-  switch (node->type)
-    {
-    case CHARACTER:
-      if (node->opr.c != ch)
-        return false;
-      break;
-
-    case SIMPLE_BRACKET:
-      if (!bitset_contain (node->opr.sbcset, ch))
-        return false;
-      break;
-
-#ifdef RE_ENABLE_I18N
-    case OP_UTF8_PERIOD:
-      if (ch >= ASCII_CHARS)
-        return false;
-      /* FALLTHROUGH */
-#endif
-    case OP_PERIOD:
-      if ((ch == '\n' && !(mctx->dfa->syntax & RE_DOT_NEWLINE))
-	  || (ch == '\0' && (mctx->dfa->syntax & RE_DOT_NOT_NULL)))
-	return false;
-      break;
-
-    default:
-      return false;
-    }
-
-  if (node->constraint)
-    {
-      /* The node has constraints.  Check whether the current context
-	 satisfies the constraints.  */
-      unsigned int context = re_string_context_at (&mctx->input, idx,
-						   mctx->eflags);
-      if (NOT_SATISFY_NEXT_CONSTRAINT (node->constraint, context))
-	return false;
-    }
-
-  return true;
-}
-
-/* Extend the buffers, if the buffers have run out.  */
-
-static reg_errcode_t
-internal_function
-extend_buffers (re_match_context_t *mctx)
-{
-  reg_errcode_t ret;
-  re_string_t *pstr = &mctx->input;
-
-  /* Avoid overflow.  */
-  if (BE (SIZE_MAX / 2 / sizeof (re_dfastate_t *) <= pstr->bufs_len, 0))
-    return REG_ESPACE;
-
-  /* Double the lengthes of the buffers.  */
-  ret = re_string_realloc_buffers (pstr, pstr->bufs_len * 2);
-  if (BE (ret != REG_NOERROR, 0))
-    return ret;
-
-  if (mctx->state_log != NULL)
-    {
-      /* And double the length of state_log.  */
-      /* XXX We have no indication of the size of this buffer.  If this
-	 allocation fail we have no indication that the state_log array
-	 does not have the right size.  */
-      re_dfastate_t **new_array = re_realloc (mctx->state_log, re_dfastate_t *,
-					      pstr->bufs_len + 1);
-      if (BE (new_array == NULL, 0))
-	return REG_ESPACE;
-      mctx->state_log = new_array;
-    }
-
-  /* Then reconstruct the buffers.  */
-  if (pstr->icase)
-    {
-#ifdef RE_ENABLE_I18N
-      if (pstr->mb_cur_max > 1)
-	{
-	  ret = build_wcs_upper_buffer (pstr);
-	  if (BE (ret != REG_NOERROR, 0))
-	    return ret;
-	}
-      else
-#endif /* RE_ENABLE_I18N  */
-	build_upper_buffer (pstr);
-    }
-  else
-    {
-#ifdef RE_ENABLE_I18N
-      if (pstr->mb_cur_max > 1)
-	build_wcs_buffer (pstr);
-      else
-#endif /* RE_ENABLE_I18N  */
-	{
-	  if (pstr->trans != NULL)
-	    re_string_translate_buffer (pstr);
-	}
-    }
-  return REG_NOERROR;
-}
-
-
-/* Functions for matching context.  */
-
-/* Initialize MCTX.  */
-
-static reg_errcode_t
-internal_function
-match_ctx_init (re_match_context_t *mctx, int eflags, Idx n)
-{
-  mctx->eflags = eflags;
-  mctx->match_last = REG_MISSING;
-  if (n > 0)
-    {
-      /* Avoid overflow.  */
-      size_t max_object_size =
-	MAX (sizeof (struct re_backref_cache_entry),
-	     sizeof (re_sub_match_top_t *));
-      if (BE (SIZE_MAX / max_object_size < n, 0))
-	return REG_ESPACE;
-
-      mctx->bkref_ents = re_malloc (struct re_backref_cache_entry, n);
-      mctx->sub_tops = re_malloc (re_sub_match_top_t *, n);
-      if (BE (mctx->bkref_ents == NULL || mctx->sub_tops == NULL, 0))
-	return REG_ESPACE;
-    }
-  /* Already zero-ed by the caller.
-     else
-       mctx->bkref_ents = NULL;
-     mctx->nbkref_ents = 0;
-     mctx->nsub_tops = 0;  */
-  mctx->abkref_ents = n;
-  mctx->max_mb_elem_len = 1;
-  mctx->asub_tops = n;
-  return REG_NOERROR;
-}
-
-/* Clean the entries which depend on the current input in MCTX.
-   This function must be invoked when the matcher changes the start index
-   of the input, or changes the input string.  */
-
-static void
-internal_function
-match_ctx_clean (re_match_context_t *mctx)
-{
-  Idx st_idx;
-  for (st_idx = 0; st_idx < mctx->nsub_tops; ++st_idx)
-    {
-      Idx sl_idx;
-      re_sub_match_top_t *top = mctx->sub_tops[st_idx];
-      for (sl_idx = 0; sl_idx < top->nlasts; ++sl_idx)
-	{
-	  re_sub_match_last_t *last = top->lasts[sl_idx];
-	  re_free (last->path.array);
-	  re_free (last);
-	}
-      re_free (top->lasts);
-      if (top->path)
-	{
-	  re_free (top->path->array);
-	  re_free (top->path);
-	}
-      free (top);
-    }
-
-  mctx->nsub_tops = 0;
-  mctx->nbkref_ents = 0;
-}
-
-/* Free all the memory associated with MCTX.  */
-
-static void
-internal_function
-match_ctx_free (re_match_context_t *mctx)
-{
-  /* First, free all the memory associated with MCTX->SUB_TOPS.  */
-  match_ctx_clean (mctx);
-  re_free (mctx->sub_tops);
-  re_free (mctx->bkref_ents);
-}
-
-/* Add a new backreference entry to MCTX.
-   Note that we assume that caller never call this function with duplicate
-   entry, and call with STR_IDX which isn't smaller than any existing entry.
-*/
-
-static reg_errcode_t
-internal_function
-match_ctx_add_entry (re_match_context_t *mctx, Idx node, Idx str_idx, Idx from,
-		     Idx to)
-{
-  if (mctx->nbkref_ents >= mctx->abkref_ents)
-    {
-      struct re_backref_cache_entry* new_entry;
-      new_entry = re_realloc (mctx->bkref_ents, struct re_backref_cache_entry,
-			      mctx->abkref_ents * 2);
-      if (BE (new_entry == NULL, 0))
-	{
-	  re_free (mctx->bkref_ents);
-	  return REG_ESPACE;
-	}
-      mctx->bkref_ents = new_entry;
-      memset (mctx->bkref_ents + mctx->nbkref_ents, '\0',
-	      sizeof (struct re_backref_cache_entry) * mctx->abkref_ents);
-      mctx->abkref_ents *= 2;
-    }
-  if (mctx->nbkref_ents > 0
-      && mctx->bkref_ents[mctx->nbkref_ents - 1].str_idx == str_idx)
-    mctx->bkref_ents[mctx->nbkref_ents - 1].more = 1;
-
-  mctx->bkref_ents[mctx->nbkref_ents].node = node;
-  mctx->bkref_ents[mctx->nbkref_ents].str_idx = str_idx;
-  mctx->bkref_ents[mctx->nbkref_ents].subexp_from = from;
-  mctx->bkref_ents[mctx->nbkref_ents].subexp_to = to;
-
-  /* This is a cache that saves negative results of check_dst_limits_calc_pos.
-     If bit N is clear, means that this entry won't epsilon-transition to
-     an OP_OPEN_SUBEXP or OP_CLOSE_SUBEXP for the N+1-th subexpression.  If
-     it is set, check_dst_limits_calc_pos_1 will recurse and try to find one
-     such node.
-
-     A backreference does not epsilon-transition unless it is empty, so set
-     to all zeros if FROM != TO.  */
-  mctx->bkref_ents[mctx->nbkref_ents].eps_reachable_subexps_map
-    = (from == to ? -1 : 0);
-
-  mctx->bkref_ents[mctx->nbkref_ents++].more = 0;
-  if (mctx->max_mb_elem_len < to - from)
-    mctx->max_mb_elem_len = to - from;
-  return REG_NOERROR;
-}
-
-/* Return the first entry with the same str_idx, or REG_MISSING if none is
-   found.  Note that MCTX->BKREF_ENTS is already sorted by MCTX->STR_IDX.  */
-
-static Idx
-internal_function
-search_cur_bkref_entry (const re_match_context_t *mctx, Idx str_idx)
-{
-  Idx left, right, mid, last;
-  last = right = mctx->nbkref_ents;
-  for (left = 0; left < right;)
-    {
-      mid = (left + right) / 2;
-      if (mctx->bkref_ents[mid].str_idx < str_idx)
-	left = mid + 1;
-      else
-	right = mid;
-    }
-  if (left < last && mctx->bkref_ents[left].str_idx == str_idx)
-    return left;
-  else
-    return REG_MISSING;
-}
-
-/* Register the node NODE, whose type is OP_OPEN_SUBEXP, and which matches
-   at STR_IDX.  */
-
-static reg_errcode_t
-internal_function
-match_ctx_add_subtop (re_match_context_t *mctx, Idx node, Idx str_idx)
-{
-#ifdef DEBUG
-  assert (mctx->sub_tops != NULL);
-  assert (mctx->asub_tops > 0);
-#endif
-  if (BE (mctx->nsub_tops == mctx->asub_tops, 0))
-    {
-      Idx new_asub_tops = mctx->asub_tops * 2;
-      re_sub_match_top_t **new_array = re_realloc (mctx->sub_tops,
-						   re_sub_match_top_t *,
-						   new_asub_tops);
-      if (BE (new_array == NULL, 0))
-	return REG_ESPACE;
-      mctx->sub_tops = new_array;
-      mctx->asub_tops = new_asub_tops;
-    }
-  mctx->sub_tops[mctx->nsub_tops] = calloc (1, sizeof (re_sub_match_top_t));
-  if (BE (mctx->sub_tops[mctx->nsub_tops] == NULL, 0))
-    return REG_ESPACE;
-  mctx->sub_tops[mctx->nsub_tops]->node = node;
-  mctx->sub_tops[mctx->nsub_tops++]->str_idx = str_idx;
-  return REG_NOERROR;
-}
-
-/* Register the node NODE, whose type is OP_CLOSE_SUBEXP, and which matches
-   at STR_IDX, whose corresponding OP_OPEN_SUBEXP is SUB_TOP.  */
-
-static re_sub_match_last_t *
-internal_function
-match_ctx_add_sublast (re_sub_match_top_t *subtop, Idx node, Idx str_idx)
-{
-  re_sub_match_last_t *new_entry;
-  if (BE (subtop->nlasts == subtop->alasts, 0))
-    {
-      Idx new_alasts = 2 * subtop->alasts + 1;
-      re_sub_match_last_t **new_array = re_realloc (subtop->lasts,
-						    re_sub_match_last_t *,
-						    new_alasts);
-      if (BE (new_array == NULL, 0))
-	return NULL;
-      subtop->lasts = new_array;
-      subtop->alasts = new_alasts;
-    }
-  new_entry = calloc (1, sizeof (re_sub_match_last_t));
-  if (BE (new_entry != NULL, 1))
-    {
-      subtop->lasts[subtop->nlasts] = new_entry;
-      new_entry->node = node;
-      new_entry->str_idx = str_idx;
-      ++subtop->nlasts;
-    }
-  return new_entry;
-}
-
-static void
-internal_function
-sift_ctx_init (re_sift_context_t *sctx, re_dfastate_t **sifted_sts,
-	       re_dfastate_t **limited_sts, Idx last_node, Idx last_str_idx)
-{
-  sctx->sifted_states = sifted_sts;
-  sctx->limited_states = limited_sts;
-  sctx->last_node = last_node;
-  sctx->last_str_idx = last_str_idx;
-  re_node_set_init_empty (&sctx->limits);
-}
